Disney is embarking on a new era of not just streaming, but also meta and musicals. With the November release of Disney+, its exclusive streaming platform, as High School Musical: The Musical: The Series makes its debut on the platform. The show is built around the adolescent romance of two teens who are starring in their high school’s stage production of the 2006 Disney Channel movie High School Musical — which is about, naturally, the adolescent romance of two teens who are starring in their high school’s musical.

If that’s not enough of a mindbender for you, the new series is full of additional meta-references to both High School Musical and its real-life fandom. Not only does HSM:THM:TS recreate famous songs and plot beats from the movie, but it also features fictional characters in the show who are obsessed with that movie, and its numerous sequels and spinoffs.

You might be wondering whether there’s any fandom left for the franchise, given that its last major film, Sharpay’s Fabulous Adventure, premiered on Disney Channel all of 8 years ago. But don’t underestimate the zealotry that the New York Times once dubbed “a new religion:” Among the most recent of the world’s HSM converts is YouTube star Trisha Paytas, who just a few weeks ago dropped a shot-for-shot remake of one of the franchise’s best-known musical numbers, filmed on location at the titular high school itself.

Confused by this litany of meta-references to musicals about high school, musicals about high school musicals, and TV shows about fake fans of real meta-musicals that reference real-life meta-fandoms? Then it may be the perfect moment to discover why High School Musical was such a huge cultural phenomenon — and why so many people are still obsessed with the series.

HSM grapples with the eternal high school question: conform or be yourself?

High School Musical is nominally about a romance between Troy (Zac Efron) and Gabriella (Vanessa Hudgens), two teens who meet at a holiday ski lodge where they’re unexpectedly thrust together to sing karaoke. Efron’s and Hudgens’ instant chemistry in this number, “Start of Something New,” is a huge part of the film’s success, kicking things off on a strong note, and making it clear that you’re here for love.

Unfortunately for Troy and Gabriella, their star-crossed love has some hurdles to overcome. After this romantic moment, they meet up after the winter break when Gabriella magically transfers to Troy’s school, where things aren’t quite as rosy.

If that plot sounds like it’s borrowed from another famous high school-set musical, Grease, your instincts are correct. Screenwriter Peter Barsocchini, who based the film on his daughter and most of her friends, turned to Grease for the film’s main plot beats, including the existential conflict every teenager faces: Do you conform to your place within the rigid high school social hierarchy? Or do you break free and follow your heart?

In High School Musical, it’s Troy who has to make this harrowing choice, and thanks to Zac Efron being one of the world’s hammiest actors, High School Musical becomes a veritable Hamlet of indecision. See, Troy’s social position is leader of the high school basketball team, but what he really wants to do is sing the lead in the school musical, a fictional show called “Twinkle Town,” with Gabriella. This conflict propels the film, as Troy has to grapple repeatedly with how seriously to pursue this acting thing, and then later wrestles with how to follow his acting dreams — he even gets accepted to Juilliard — while still keeping Gabriella in his life.

Buffeting him to and fro is a cast of addictive side-characters, in particular Corbin Bleu as Troy’s basketball bro Chad, and Ashley Tisdale and Lucas Grabeel as two spoiled, scheming siblings, Sharpay and Ryan, who want the leads in the musical for themselves. Yes, that’s incestuous, but the musical delights in this kind of subtle over-the-top parody of itself, as you can see in numbers like “Stick to the Status Quo:”

Thematically, HSM isn’t anything splashy, and its score is all over the place — probably because fully a dozen songwriters contributed song material to the immensely popular soundtrack. But it has a secret weapon: It’s directed and choreographed by longtime Disney collaborator Kenny Ortega, the man who choreographed Dirty Dancing and brought the world the cult classic musical Newsies (1992), and who has worked with many of the world’s biggest pop idols, including Michael Jackson and Cher. Ortega keeps HSM just sincere enough to be endearing and just tongue-in-cheek enough to keep it from devolving into pure camp, and he also gifts it with plenty of great dance numbers. Take, for instance, the basketball dance from “Getcha Head in the Game,” which incidentally features the immortal line, “My head’s in the game, but my heart’s in the song.” Who among us can’t relate?

Troy and Gabriella’s friends and enemies alternately conspire to help or prevent them from realizing their theatrical dreams. In the end, through a series of highly implausible plot twists (let’s just say it involves asking a lot from electricity), Troy and Gabriella fall in love, win the leads in the school play, and Troy gets to lead the basketball team to victory! Guys, it’s perfect. And although this plot makes very little sense, HSM combined zany whimsy with wink-wink-nod affection for its own tropes, and had a deeply earnest, if rosy, look at the pressures of high school and the thrill of teenage romance. In other words, it was pure tween-bait, and looking back, it’s easy to understand why the movie became an instant phenomenon.

High School Musical was one of the most successful original movies to air on the Disney Channel to date, pulling in ratings of nearly 8 million viewers. But in 2006, many reviewers considered its overnight popularity to be a flash in the pan. New York Times critic Charles Isherwood, reviewing Disney’s live, touring stage production a year later, could barely mask his disdain when he wrote, “[The characters] find true fulfillment and express their individuality by trying out for the school musical. Anyway ...”

Still, the first film established an enormous fanbase for HSM. High School Musical’s soundtrack went triple platinum, and its subsequent concert tour grossed $33 million. And it was about to get much bigger.

High School Musical was an unexpected overnight sensation. Its sequel was even bigger.

High School Musical had the basic ingredients every musical needs to succeed — an engaging cast, catchy songs, and a relatable theme. But it also had something perhaps even more crucial: perfect timing.

The first High School Musical is a Disney Channel Original Movie (DCOM), which didn’t really mean much at the time unless you are a certain brand of millennial or Gen Z-er who’d grown up on little-known, forgettable films of the late ‘90s and early Aughts aimed squarely at children. By 2006, the network’s biggest DCOM to date had been 2002’s Cadet Kelly, a “poor little rich girl” romp piggy-backing off the success of its star, Lizzie McGuire’s Hilary Duff. But most original Disney channel films starred relative unknowns, and few viewers outside cult fans and kids who’d grown up with the Disney Channel were paying attention to titles like Life is Ruff (2005) or Stuck in the Suburbs (2004).

But in 2006, High School Musical broke away from this trend immediately. Not only was it the rare Disney Channel movie aimed at teens and “tweens” rather than kids, but it was one of the relative few at the time that boasted its own soundtrack. And it was a “true” musical — the songs were integrated into the story conceit, meaning that rather than songs originating from the characters’ fictional world, like being played on someone’s radio, they’re instead performed by characters expressing their feelings and intentions through song.

Ingeniously, the very first scene of the movie is a famous exception to this rule. The song Troy and Gabriella sing together, “Start of Something New,” works on several levels at once to introduce audiences into the world of High School Musical. It’s a fictional karaoke song written just for the film, ushering us gently into a world where the characters break into songs we’ve never heard before. “Start of Something New” also announces itself as something new among original Disney Channel movies: a cheeky meta-commentary that will still deliver the familiar tropes you expect.

And perhaps most crucially for Disney as a marketer of pop music and pop icons, “Something New” is a giant megaphone shouting at you to pay attention to Efron and Hudgens. Here they are, your new pop idols, already earworming their way into your hearts.

Until that point in its lifespan, Disney hadn’t really gotten comfortable parodying its own brand; the brief meta-jokes that distinguished animated films Aladdin (1992) and The Emperor’s New Groove (2000) from more self-serious entries in the Disney canon made them unique outliers, rather than evidence that the Mouse was growing more open to affectionate self-sendups. But ever since 2001’s The Producers, based on Mel Brooks’ 1967 film, the Broadway musical had been fair game for self-parody, and this combination proved to be killer: Disney couldn’t effectively parody its existing brand, but it could create a new sub-brand of musical films that played up its tropes and targeted self-aware Disney fandom, all while marketing itself around performers who doubled as pop singers. This formula was an instant success: High School Musical drew ratings of nearly 8 million viewers on its first showing, one of the biggest audiences in history for a DCOM at that point.

Efron and Hudgens became overnight celebrities — he got a Rolling Stone profile; she had to apologize for having her private racy photos leaked. Globally, Disney poured money into expanding the franchise, investing in international HSM remakes, localized versions of the music videos, creating an entirely new Hindi soundtrack, and even creating three separate variants of a new Spanish-language film, High School Musical: El Desafío (The Challenge), for Argentinian, Brazilian, and Mexican audiences.

Time reported in 2008 that the franchise had reaped nearly $700 million in soundtrack and merchandise sales. The third movie, High School Musical 3, leveled up to a major theatrical release in 2008 that grossed over $250 million at the box office. The stage version of High School Musical — the one now featured in the new TV series — appeared in 2006 and instantly became widely performed.

Among these many offshoots, it was 2007’s High School Musical 2 that really cinched the franchise’s place within the mainstream. Upon its premiere, HSM2 drew an audience of over 17 million viewers — the highest ratings for an original cable movie in history.

There are only two things you really need to know about High School Musical 2. One is that every song in it is a showcase for the cast members, by now all well-established as minor divas in their own right. In particular, Sharpay’s song “Fabulous” sets the tone for the movie as a whole, with its lyrical emphasis on being bigger and better. Meanwhile, there’s a lot of dancing in incongruous locations. Ryan very straightforwardly pulls off dance moves on a baseball mound, while Troy leads the ensemble in a country club kitchen workout, and then, most iconically of all, dances across a golf course in what may go down in history as the Single Most Important Musical Number of Our Time: “Bet On It.” Although Hudgens sang her part, most of Efron’s vocals for the first film were overdubbed by veteran Disney artist Drew Seeley, something Efron fought successfully to change for the two sequels. That may have helped to give this song that extra bit of iconic pizzazz:

The other thing to know is that High School Musical 2 changed everything about the Disney Channel Original Movie. Overnight, the approach Disney had taken with the first musical kicked into high gear. After HSM2, numerous DCOMs were savvily marketed as vehicles for their burgeoning pop stars — like 2008’s Camp Rock, which became a significant launchpad for its stars Demi Lovato and the Jonas Brothers, 2009’s Wizards of Waverly Place movie, which similarly served its star Selena Gomez, and 2011’s HSM spinoff focused on Ashley Tisdale, Sharpay’s Fabulous Adventure. Above all, this new focus on targeting teens and pre-teens with teen celebs singing original music made the DCOM into its own distinctive Thing.

Nearly all of these movies were hits. In fact, by the time 2013’s Teen Beech Movie became the second-highest-rated original cable movie ever, numerous DCOMs were among the top 10 listings. And this typical number from Teen Beech Movie, below, shows exactly just how expert Disney had become at gifting its fans with genre-savvy musical films full of deliberate camp following HSM’s success.

But arguably, High School Musical’s truest legacy has been its impact on modern musicals — in that its success helped usher in a new era of unironic love for musical theatre, and a new approach to integrating the musical into the mainstream.

High School Musical made it okay to like musicals again

Even if all High School Musical did was spawn its own hardcore fandom and spinoff productions, and lead to the rise of the DCOM, it would still arguably be a mainstream topic today. But in fact, HSM did so much more than this. High School Musical arguably single-handedly led to the cultural resurgence of musicals in the modern era.

The year 2007 alone saw a string of popular movie musicals capitalizing on the moment, like Hairspray, Disney’s own Enchanted, Once, and Sweeney Todd, all dripping in self-commentary on their respective genres and tropes. This trend has continued into the 2010s with an ongoing lineup of regular movie musicals from Les Miserables and Into the Woods to the upcoming Spielberg-directed West Side Story remake, and eventually expanded into the recent hit-and-miss but popular tradition of live stage musical performances.

Without High School Musical, we definitely wouldn’t have Glee, or the cult favorite musical TV series Smash, or the Pitch Perfect franchise. HSM also arguably paved the way for the success of Joss Whedon’s 2008 cult hit musical, Dr Horrible’s Sing-along Blog. These were all works whose popularity derived in part from their fans being in on the “joke” about how uncool it is to like musicals and singing groups — thus ironically making it okay for musicals and singing groups to become cool again. In the years since, this mixing of meta and musicals has given us whole new levels of integrated musical performances, in everything from Coen Brothers’ films to Netflix satires to Crazy Ex Girlfriend’s entire existence.

High School Musical arguably directly led to the successful careers of Hudgens, Efron, Lovato, Gomez, and the Jonas Brothers, a pretty jaw-dropping litany of pop idols. And not to leave out the internet, HSM gave us a litany of beloved memes and references, from Troy skipping across a golf course to Sharpay and Ryan doing basically anything.

The series’ musical numbers, particularly from the first two films, have since been referenced and parodied repeatedly throughout pop culture, from a MadTV sketch (starring Key and Peele) to South Park to the rare Disney-sanctioned YouTube riff, to this In the Heights promo Lin Manuel-Miranda did that I don’t know why we don’t talk about all the time?!

There’s even a Suite Life of Zack & Cody episode built around the stage production of High School Musical that in many ways seems to have served as a template for the current HSM series, somehow combining a double reference to Singing in the Rain and HSM while roping Tisdale in for some meta-casting:

The early reviews of High School Musical: The Musical: The Series indicate that the show’s not exactly breaking new and innovative ground — it’s a mockumentary-style riff on the production that seems to have more in common with HSM’s successor, Glee, than to the franchise itself.

But perhaps the High School Musical franchise has already broken so much ground that its creative team — including series showrunner Tim Federle, a man who’s written entire books about how much floundering teens need the theatre — feels that all it needs to be is an inspiration to its successors.

And given just how inspiring it’s proven to be, who are we to argue?