Jane Lynch and Matthew Morrison

Lots has happened to McKinley High's ragtag glee club over the summer. One original member of New Directions transferred to a new school. Quinn lost her baby weight. Finn and Rachel are still together, but Artie got dumped. So did Terri. And Coach Tanaka.

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The first day back at school brings even more surprises. In Glee's second season premiere, which Fox screened for a lucky crowd on Tuesday, Rachel will meet her new competition, Finn will bust a move for Coach Sue, Mr. Schu will make an unlikely ally, the football team will get to know its new coach, and two potential glee club recruits will meet the gang. TVGuide.com spoke to the writers and cast at the afterparty, and present these 10 semi-spoilery highlights:

Shaft is out. New Directions will start the season one man down. Matt (Dijon Talton), aka Shaft, according to Coach Sue (Jane Lynch), has left McKinley. His smooth moves were sort of overshadowed by fellow football player-turned-glee clubber Mike Chang (Harry Shum). Did Matt even speak? We honestly don't recall. But he was one of the starting 12, and because of that we will miss him. Then again, that means there are openings...

The new kids can sing. Pint-sized dynamo Sunshine Corazon (guest star Charice) will not only engage in a mini-sing-off with super-jealous Rachel (Lea Michele), she'll take the stage solo for a diva-licious number from Dreamgirls. (Hint: It's the one they added to the movie so Beyonce wouldn't play second banana to Jennifer Hudson's "And I Am Telling You.") Meanwhile, reluctant, pouty-mouthed glee clubber Sam (Chord Overstreet) will jam with the boys to Travie McCoy's aspirational-if-obnoxious acoustic tune "Billionaire." As sung by Overstreet, however, it's simple and lovely.

Someone got a boob job. But we can't say who. Let's just say her new pair will put her at the bottom of the pyramid.

Cory Monteith is slimming down for the Rocky Horror episode. Why? You may have heard Lea Michele give it away at the Emmys: Finn is going to be donning the infamous mankini. (Matthew Morrison too? Maybe.) Monteith, who plays Finn, says he's been running laps and eating lots of chicken breast to prepare. "I just think if I'm going to be taking the shirt off and wearing the mankini, I owe it to our viewers. Really," the actor says. But a strict regimen is not what he prefers. "If no one cared, I would not work out."

Elsewhere in the episode, Emma (Jayma Mays) will be singing the risqué "Touch-A Touch-A Touch Me," says co-executive producer Ian Brennan. Does this mean Mr. Schu (Matthew Morrison) will get lucky? Or her new dentist beau Dr. Carl Howell (John Stamos)? Both will appear in the episode, set to air on Halloween. Fun fact: Mays actually sang the song for her Glee audition — so she knows it pretty well.

Tina likes abs. Hold the "Poor Artie." It turns out that Artie (Kevin McHale) wasn't the best boyfriend over the summer. Something about a Halo marathon taking up his time? Tina (Jenna Ushkowitz) couldn't help but stray to the well-defined, six-pack abs of Mike while the two attended Asian Camp together. Yeah, it's like band camp, only for Asians.

Terri will get a new man. Terri (Jessalyn Gilsig) isn't in the first episode — and neither is Emma, in case you're wondering — but Gilsig says Mr. Schu's ex is waiting in the wings. And she's not alone. "I'm going to start a relationship with somebody, and it's going to, by its nature, put me around Will," she says. Before you start flashing back to the weirdness between Finn and Terri last season, the actress assures us that Terri won't be dating a student. A teacher perhaps? Someone of "authority," she says.

Did we mention the premiere's catfight? Slapping, smack-talking, slamming into lockers — it's the real deal. Not everyone is happy that Quinn is back on top of the Cheerios.

Finn will have a crisis of faith. At least, that's what we're assuming. Monteith says Finn will have lots to do in Glee's third episode, which is all about religion. We've already heard that Mercedes (Amber Riley) will be bringing Kurt (Chris Colfer) to church with her, and now we also know that Finn will be singing REM's "Losing My Religion." Monteith adds only that Finn has plenty on his mind at that moment.

Rachel gets another aggressive suitor. For a spotlight—hogging choir girl, Rachel sure does attract a lot of boys. Last year she made out with Puck (Mark Salling), dated Jesse St. James (Jonathan Groff), and still wound up with Finn. Who's next? Josh Sussman, who plays McKinley's roving gossip blogger Jacob, says he'll be getting a shot — sort of. "My character is hornier than ever," Sussman says. "[I'm going] after Rachel Berry. In Season 1, I wanted to see her bra, then I got Rachel Berry panties. Now I want more, and I go for it."

Brittany will have a boyfriend. Or a girlfriend. Heather Morris, who plays the ditsy Cheerio, wouldn't say either way. "I have a relationship with another glee club member. Whether it's a boy or girl, I don't know... I don't kiss and tell." Ah, but there is that kiss she'll share with Santana (Naya Rivera), right? Maybe it will be more than a fleeting girl-on-girl moment?

Check out a sneak peek of the season premiere here:

Glee returns Sept. 21 on Fox.

(Additional reporting by Natalie Abrams and Kate Stanhope)