t the studio and back lot of Epitome Pictures, in an industrial part of Toronto, every day was prom night. Tarps covered windows to keep out the sun. Dozens of gangly kids in ill-fitting formal wear swayed to a loop of dance rock in a gym tricked out with blue and yellow balloons. During breaks, 15-year-olds grabbed lunch in the set's shrunken cafeteria. Steps away from a hall lined with scratched-up lockers, a hidden staircase led to the cast's tutoring room, where a few school-age actors logged face time. Some were solving equations, others goofed off, charting city routes on a laptop flight simulator. A boy half sang, half translated the opening number from ''Cabaret.''

Outside the tutoring room, Melissa McIntyre, an 18-year-old actress with shimmering rock-chick makeup and dark choppy hair, was destroying her laconic co-star, Shane Kippel, at foosball. After scoring the final goal, McIntyre hooted and just about vaulted onto the game table, a blur of bare arms and boots. For those who know her only from ''Degrassi: The Next Generation,'' Epitome's international cult-hit TV show for teenagers, the victory dance was hard to believe -- like catching James Gandolfini arranging daisies in a glass vase. Ashley, the avenging, depressive good girl McIntyre has played for four years, never celebrates, even on those rare occasions when she wins something. From her first appearance as a sibilant 14-year-old priss, Ashley has followed the quintessential parents'-nightmare story arc: class president to class pariah to lovelorn loner, messing with drugs, disloyal friends and wretched poetry along the way.

''I think the biggest thing with Ashley,'' McIntyre said as she collapsed into a beat-up easy chair, ''is she goes through a lot, and she doesn't really always handle it that well.'' She gently wrinkled her face, as if she couldn't believe she plays such a killjoy. ''But you can tell that she learns from it as she goes along.''

She'd better not learn too quickly. This season, after reuniting with her unfaithful bipolar boyfriend and losing her virginity to him on the night of her father's gay wedding, an unusual thing happened to Ashley: she actually matured, became supportive, the typical TV girlfriend. Luckily for McIntyre, by season's end -- August in the United States -- Ashley will return to her self-absorbed, drama-queen roots in a cliffhanger that reduces the person closest to her to a homeless, quivering wreck.

Filmed in a sitcom-vérité style, with a cast of actors who really are teenagers, ''Degrassi: The Next Generation'' confronts controversy in a way that American network television wouldn't dream of. A 15-year-old boy uses a penis pump when he discovers he's not as endowed as his rival for his girlfriend's affection. A mousy 13-year-old who wants to be ''hot'' stops wearing underwear to school. A 17-year-old girl wonders whether to abandon her alcoholic mother and move in with her boyfriend.

The ensemble -- Ashley and a dozen or so students in overlapping social circles -- have lived through date rape, pedophile cyberstalking, the agony and ecstasy of coming out, drug abuse, discrimination against a plus-size teen model, abusive boyfriends, gay boyfriends who are too out, a school shooting, abortion, ADD, Ritalin abuse, dyscalculia, paraplegia, genetically modified food in the cafeteria, boyfriend poaching, a gonorrhea outbreak, classism, male bulimia and . . . you get the idea. Though the explosive-issue-per-capita ratio is seriously out of whack (and you'd probably not want your kid to attend Degrassi for that reason), the teen-diary attention to B-plot microissues (zits, periods, parents' night) gives the episodes a peculiar authenticity no matter how outrageous their story lines. Without much help from parents and teachers, kid characters try to figure out their lives, and kid viewers around the world second-guess them. That's what the show's creator and executive producer, 57-year-old Linda Schuyler, a former junior-high-school teacher, wants.

She and the head writer, Aaron Martin, have often disagreed, she told me nonchalantly, leaning forward in her light-filled office in Epitome's executive wing. Citing responsibility fatigue, Martin had announced that he was leaving the show at the end of the season, but Schuyler, who is maternal in a distant way, wasn't slowing down to mourn. In tight jeans and boots, she sat facing away from her plasma-TV monitor, resisting the temptation to oversee that day's shooting. ''Aaron doesn't have the educational background,'' she continued. ''I maintain that one of the things that makes 'Degrassi' work is that we do quite gracefully blend education and entertainment, but I am completely aware that you have to entertain first. It's not that I want to do a string of P.S.A.'s, but Aaron's background is completely entertainment -- we pull against each other from time to time because he feels that I'm being too intense and messagey, and I feel that he's losing the intent of the show.''

Schuyler's insistence on a mix of extreme youthful dysfunction and ''messaging,'' stopping short of public service announcements, is why ''Degrassi'' -- or rather the ''Degrassi'' franchise -- is celebrating its 25th anniversary this year. The current show is the latest iteration in a series that began in 1980 as ''Kids of Degrassi Street,'' a quasi-documentary project that emerged out of theater workshops with local kids. It evolved after a five-year run into the more tightly scripted ''Degrassi Junior High,'' which ran for three years, to be followed by two years of ''Degrassi High.'' That series revolved around a group of kids, tracking them from the beginning of junior high until high-school graduation, using actors whose ages were within one or two years of the characters they played, carrying story lines from season to season without ever entirely resolving them. (The story was finally completed in a TV movie of the week called ''School's Out,'' broadcast in 1991.)

From its heyday in the late 1980's until its current renaissance, the ''Degrassi'' series thrived as a cultish, almost accidental, phenomenon. In the United States, the shows ran on public-TV stations; abroad, they survived an international time and culture lag, selling, sometimes years after they were first broadcast, in 150 foreign markets, including Afghanistan, Algeria, Bangladesh, all of Europe, China, Equatorial Guinea, South and North Korea, Israel, Kuwait, Macao, Myanmar, Nepal, Pakistan, Iran and Rwanda. They also ran in Cuba, where a graduate student in cultural anthropology doing field research discovered that the ''Degrassi'' shows were lauded for being educational and endorsing values like ''family and generosity.''

And so it would probably have continued -- with nostalgic fans annotating devotional Web sites, gathering to screen 20-year-old episodes in hipster enclaves like Austin, Tex., and Williamsburg, Brooklyn, and writing theoretical essays, like the ones now collected in an anthology called ''Growing Up Degrassi,'' to be published next fall. But when the first episode of Season 4 of ''Degrassi: The Next Generation'' had its premiere on the N, Viacom's three-year-old digital cable channel, last October, it came in as the highest-rated program of the night among teenagers in all of broadcast and cable television, beating out even supermainstream youth shows like ''Joan of Arcadia'' and ''8 Simple Rules.'' The N claims that the network attracts a higher concentration of 12- to 17-year-old girls than competitors like MTV and ABC Family and of teenagers as a whole than YM and Teen People. This is remarkable because the N is available in only 44 million U.S. homes. And network executives say there's room for another spike in viewers. ''One of the truisms of television is that drama doesn't repeat. . . . 'Degrassi' repeats like nobody's business,'' Sarah Tomassi Lindman, head of programming for the N, told me. Indeed, the N really does repeat the show like nobody's business, sometimes up to 20 hours a week, so much so that some ''Degrassi'' fans refer to the N as ''the Degrassi Network.''

The cast, which attracts a reserved following in Canada, has excited a much more passionate response among a segment of their core demographic in the United States. During the summer of 2004, the N brought cast members to the States for sneak screenings at Madison Square Garden and other urban locations, and then again for mall tours, the kinds of events that record labels use to stoke interest in teen-pop musicians like Avril Lavigne. With only the N's on-air and online promotion -- and some local coverage -- fans swarmed the food courts. In Atlanta, Boston, Los Angeles and Dallas, teenagers lined up for hours to get autographs from cast members. In Honolulu, shrieking kids wearing homemade ''I Love Ashley'' T-shirts gave Melissa McIntyre candy leis they had strung themselves.

The paucity of official ''Degrassi'' swag only adds to the show's punkette, do-it-yourself appeal. During an episode in which Ashley and her sometime boyfriend Craig compete against each other in a battle of the bands, the N flashed an on-screen message urging kids to ''Give Craig What He Deserves!'' and download the iron-on T-shirt logo worn by Ashley and her band mates. The image -- Craig's disembodied head engulfed in flames -- was Ashley's Photoshop revenge on him for cheating on her with a 14-year-old classmate, Manny.

The Craig-Ashley-Manny love triangle is what drew Kevin Smith -- the 34-year-old writer and director of ''Clerks'' and ''Chasing Amy'' and a longtime fan of the show's earlier incarnations -- to the current ''Degrassi.'' Now Smith is guest-starring as himself and as his cult alter ego, Silent Bob -- half the stoner-comic duo of Smith's hit movie ''Jay and Silent Bob Strike Back'' -- in a three-episode arc. Sitting at a picnic table outside the studio, waiting to shoot his own prom scenes, Smith marveled at the creative freedom Linda Schuyler enjoys. ''How awesome would it be to have your own universe, where you're telling ongoing stories, and everything is within the confines of this piece of property?'' he remarked, smiling almost sweetly. Smith, who himself manages a highly entrepreneurial universe (acting, writing comic books and scripts, running four popular Web sites, selling action figures of himself), explained the long-running appeal of ''Degrassi'' in indie-music terms. ''The garage-band ideal is where I present something to you and say, 'You've got to check this out,' '' he said. '' 'Degrassi' still has that. You can still tell more people than not about the show, and they're like, 'I've never heard about it.' Fans aren't threatened by its popularity.''

From the start, ''Degrassi'' hewed to a singular formula: telling kid stories from a kid's point of view. But that didn't stop the writers from projecting their own messages onto teen-vetted behavior. Shelley Scarrow, a 34-year-old writer of some of the show's most controversial episodes, sticks up for the sexually active girls with a big-sister fondness. ''Emma is one of the 'Everygirl' characters,'' she said, ''so when Emma's making out . . . you can pretend you're making out.'' She thinks of Ashley as her superego, and Ashley's romantic nemesis, Manny, as her id, but her face positively lights up when she talks about a minor character, ''supertrashy'' Amy, who recurs on the show only when there's a need to show extremes of drunkenness and promiscuity that the leading ladies of ''Degrassi'' won't stoop to. ''I heart Amy,'' Scarrow gushed.

Scarrow's and Canada's old-fashioned liberal openness hasn't always played well abroad: stations often choose to alter specific episodes and some have simply stopped broadcasting the show altogether. In 1988, PBS edited an abortion episode so U.S. viewers wouldn't see a teenage girl push her way through a crowd of anti-abortion protesters (shoving plastic fetuses at her) on her way to a clinic. The BBC stopped showing ''Degrassi Junior High'' following episodes that dealt with teenage pregnancy and lesbian daydreams. Deals are still pending with several Latin American countries. It's not hard to imagine the discussion in standards offices around the world about whether to show episodes like ''Secret,'' in which teenage girls (including, of course, Amy) ''earn'' brightly colored bracelets for ''hooking up'' with random guys from school, or ''Moonlight Desires,'' in which the gay class president shares a kiss with his straight male friend.

Still, the storytelling risks that ''Degrassi'' favors -- even when watered down for non-Canadians -- have more edge than those on competing shows because these kids look like real kids, with pimples, sweaty hair and tragic wardrobes. And that's because they are real kids. ''You take a 23-year-old,'' says Schuyler, ''and even if they look 100 percent believable as a 15- or 16-year-old, the performer, no matter how good an actor they are, brings with them five or six more years of life experience. 'Degrassi' is a show about firsts, so when you're doing a show about firsts, and some of your actors are really experiencing these things for the first time, there is a sincerity and an authenticity that comes through in the performance that I don't think the best actor in the world can necessarily create.''

During story meetings at the start of production each spring, the writers appraise the returning young actors, looking for changes in demeanor and appearance, keys to new story lines. They'll consult the big board on which timely social issues, written on note cards, shape the season, and right away they'll start the matching process, assigning ''issues'' -- like date rape, abortion and bullying -- to the right kid. There are always surprises. Between the first and second seasons, Shane Kippel, the 18-year-old actor who plays the cocky-yet-regretful budding villain, Spinner, lost a lot of weight, frosted his hair and suddenly found himself fast-tracked into an A plot, dating the school's queen bee, Paige. Miriam McDonald, 16, who stars as the do-gooder, Emma, went from geek to beach-blond model between Seasons 3 and 4, so the writers pinpointed the character's steely vanity and turned one of the show's gawkiest kids into a social piranha.

Schuyler has always aimed for naturalistic performances from her young actors, an aesthetic she traces to her roots as a junior-high-school teacher in the 70's. She borrowed the school's 16-millimeter camera and Nagra recorder for a documentary about first-generation immigrant kids and their experiences with racism in Canada. Realizing she'd rather be making films about young people than teaching media studies to them, she quit her job and began producing documentaries geared to a junior-high audience. Working with local school kids, Schuyler and her partner at the time, Kit Hood, created the ''Degrassi'' franchise from a patchwork of public and private money. Canadian public television and the Boston PBS affiliate, WGBH, helped finance the series.

True to its documentary roots, the last in the series, ''Degrassi High,'' ended when the kids graduated from high school, and Schuyler moved on to other television projects. In 2000, Schuyler was meeting with the programming director of CTV, Canada's leading commercial broadcaster, when she began to reminisce about ''Degrassi.'' The CTV executive, Susanne Boyce, told her, ''Linda, I don't think you're done with it.'' The premise of the new show was irresistible: in ''Degrassi Junior High,'' circa 1987, the character Spike becomes pregnant and keeps her baby. In 2001, that baby would be approaching junior-high age. Soon Schuyler and a new partner began raising money for ''The Next Generation.'' It hit the air (in Canada) that year, with a new cast of students and a handful of popular holdovers from ''Degrassi High.''

The holdovers, who call themselves Degrassi Classic, now star as parents, mentors and teachers of the new cast. With the recycling of characters and actors, plots can now span decades, drawing adult fans who remember the show's earlier incarnations. But the Classic cast often presents a challenge for the creators of the current ''Degrassi.'' ''It's a struggle,'' Shelley Scarrow said. Audiences expect old cast members to be good. ''People get mad when we make Classic cast into jerks.''

Stacie Mistysyn is familiar with the problem. She has been a ''Degrassi'' star longer than anyone -- since she was 10 years old. Every few weeks during production season, Mistysyn, who is 33, returns to the scene of her childhood TV stardom and shoots a few peripheral scenes. In Los Angeles, where she has lived for almost 10 years, Mistysyn, with her close-cropped blond hair, is one of the slim and lovely aspiring-actress masses. You can easily picture her holding her own against Kiefer Sutherland on ''24,'' authoritatively spouting off geopolitical jargon. But in Toronto she is Caitlin. Caitlin used to be at the heart of the show. (In a typically ''Degrassi'' plot twist, when Caitlin spurned one very creepy ''artsy'' boyfriend, he killed himself.) Now she's a crusading journalist, a surrogate stepmom to the hard-luck orphan, Craig, and dating her old Degrassi High boyfriend, Joey.

''We needed someone to come in and shake things up,'' Mistysyn said, as she waited to be called to the set where she'd be shooting scenes with Kevin Smith. Smith says he fell in love with Caitlin 15 years ago, when he was just a real-life convenience-store clerk. The three-episode arc -- in which Smith directs a ''Jay and Silent Bob'' movie, using ''Degrassi'' as a production set -- won't be shown in the United States until this summer, but it has already brought an abundance of grown-up press to the show in Canada. For his part, Smith is happily plugging ''Degrassi'' in sold-out speaking engagements and on his wildly popular View Askew Web site.

een life -- it's so contradictory!'' exclaimed Matthew Duntemann, the executive design director of the N, as he gestured around his office, which is decked out with time-warp youth-culture detritus: a ''Tommy Talker'' ventriloquist's dummy, an old-school Tonka dump truck, comic books both classic (''The Sea Wolf'') and contemporary (''Eightball''). The N headquarters, in Midtown Manhattan, is full of dressed-down publicists and programming executives ducking past posters of SpongeBob SquarePants. Duntemann, with his cowlicked hair, looks like a grown-up version of one of the ''alpha teens'' on the N -- hip cartoon characters who star in teasers that hype ''Degrassi'' and other series. The alpha teens were created for the N by Berkeley-based comic-book author Adrian Tomine, whose ''Optic Nerve'' series focuses on beguiling young melancholics. ''You're not afraid of them, but they're cool,'' Duntemann told me, in what might as well be the channel's operating philosophy.

The N is eager to avoid looking too forbiddingly ''New York.'' The goal is a warm, comforting ''destination'' with universal appeal. When the network first gathered focus groups to comment on ''Degrassi,'' the kids almost always guessed that it was filmed in California, despite the cast's accents and frequent mentions of Toronto. To give the channel a fresh, un-Manhattan look, its designers scouted teenagers' dressers and bedroom walls, finding inspiration in regional T-shirt logos and posters. They filmed empty schools and suburban houses in Florida, Pennsylvania and New Jersey and populated them with the Tomine cartoon kids who comment, sometimes in oblique near haiku, about the evening's programming, creating a sort of ''Degrassi'' halo effect. ''I like him,'' a cartoon girl says. ''Like a crush?'' her friend asks. ''As much as I like 'Degrassi'!'' the first responds, almost sincerely. Even if you're watching a rerun of old teenage shows like ''My So-Called Life'' or ''The Fresh Prince of Bel-Air,'' during the commercial break you're constantly reminded that a ''Degrassi'' episode is right around the corner. The latest ''Degrassi'' miniseason was moved up a week to provide the strongest possible lead-in to the network's highly promoted new show ''Miracle's Boys,'' a verite miniseries set in Harlem, with episodes directed by big names like Spike Lee and LeVar Burton.

The N is a marketer's dream come true, a TV channel that doesn't care how many 25-year-olds watch its shows. If the network has given ''Degrassi'' the highest profile the show has enjoyed in its 25-year existence, the show has repaid the favor by lending its cult legacy to a fledgling niche station. Of all the programming the N originally scheduled when it went on the air in 2002, ''Degrassi'' is the only show still playing.

But disaffected ''Degrassi'' fans find fault with a lot of things. They point to the network's habit of scheduling the show in four and five episode ''miniseasons,'' followed by months of reruns, and to the network's tendency to censor violent or potentially upsetting scenes, like the one of Craig, later found to be bipolar, facing down an oncoming train, or the scene in which Ashley has an Ecstasy-induced meltdown (at age 14). But most often, they point to ''Accidents Will Happen,'' a recent two-part episode that never played in the States because the 14-year-old Manny chose to terminate her pregnancy, yet she was spared both medical complications and lasting regret. Even in the wake of a large burst of media attention, including a discussion in The New York Times about the episode's realism and balance, and frank disappointment from the show's creative team in Toronto, the N refused to broadcast ''Accidents.'' Savvy American kids were forced to download the show from one of various unofficial ''Degrassi'' Web sites if they wanted to see it.

That's where the Donoman comes in.

''You're being banned again,'' Adam (the Donoman) Donovan, a 19-year-old moderator on Yahoo's largest ''Degrassi'' message board, e-mailed a scary fan recently. ''Congrats new record.''

Donovan, a sophomore at the University of New Hampshire, started watching the show when he was 16 and has stayed true. Together with his friend Jeremy Litwicki (who goes by the name Cerebral Assassin), he runs the site ''the Hangout,'' which just celebrated its first-year anniversary and has more than 8,000 members.

When he's not expelling stalker members who get too attached to the actors, he's promoting peer-to-peer file-sharing of shows, as well as personal remixes of favorite ''Degrassi'' story lines edited to songs by, say, Usher and Green Day. In short, a kid will reduce three years' worth of narrative to its lurid, moody essence and attach a song of the moment as the soundtrack.

One production that circulated last November starred wry 16-year-old Ellie (played by stylish Stacey Farber, 17, who was a front-row presence during Fashion Week this February). The clips showed Ellie cutting her forearms with Exacto blades, rescuing her drunken mother from their burning home and hugging her fatigues-clad father before he headed off to Afghanistan, edited to ''My Vietnam,'' a dirgelike ballad by the pop-punk singer Pink. Ellie, who suffers from a cutting compulsion, wears her red hair in braids and favors knee-high boots, gauntlets and spikes. She is a favorite of young female fans; in 2004, there was a miniepidemic of 10- to 13-year-old Quebec girls who cut their forearms in imitation of her, and during one of Farber's mall appearances, kids told her that they were dressing up as Ellie for Halloween. (At the official ''Degrassi'' Web site, kids register in faux homerooms, decorate their online lockers and speculate with grave sincerity on which character they'd be most likely to befriend if they actually attended Degrassi.)

The strength of ''Degrassi'' is that ''it feels realer than most reality shows,'' said Tom Ascheim, the 42-year-old president of Nickelodeon Digital Television and general manager of the N, as we sat in his Manhattan office. ''It feels minute-to-minute real. It feels real to our audience and real to our families.'' Still, Ascheim, who has a 12-year-old son, admits that kids are a tough audience to capture. ''You have a window. You might lose some kids at 14, 15, others at 17. You make a place for them, and for all the marketing genius you throw at a demographic, you realize you're lucky if the kids stay.''

Onstage, ashley and craig lip-synched a song that Ashley (or rather, Melissa McIntyre) wrote with the ''Degrassi'' creative team. It was an infuriatingly catchy pop-rock dance song, and some of the extras couldn't stop dancing even after shooting stopped. The lyrics, though, were typical Ashley: ''Through the mud and the dirt/All the tears and the hurt/It seared and it burned and I died.''

Craig kept looking over at Ashley, smiling, singing harmony, but for much of the song Ashley didn't meet his eyes. Every now and then, through her bangs, she'd look out at the audience. They were all dancing in time to her misery, her message. They had lived through Degrassi with her. There was her ex-boyfriend, in a wheelchair after being shot. Her little stepbrother, whose best friend was the school shooter. Manny, whom Craig got pregnant. They were all there. They'd stayed. They'd survived.