“Glee” returned to prime time Thursday night after a month-long hiatus that followed the Great Relationship Rupture-o-rama of 2012

The “Glee” cast doing a hand jive trial run. (Mike Yarish/Fox)

A bunch of stuff happened. Finn was convinced by Artie to play a key role in directing the Lima High School musical. Mercedes and Mike also returned to help with the show, because apparently their schedules as a budding L.A. recording artist and Chicago dance student, respectively, are super flexible. Coach Shannon Beiste also was back to give advice to Will and Emma about Will’s forthcoming three-month stint in Washington, D.C., allowing Dot-Marie Jones to make the first and, presumably, last Joe Theismann joke in “Glee” history.

“You looked more crooked than Joe Thiesmann’s leg,” Shannon said of the conflicted expression Emma assumed after initially agreeing to go to D.C. At that point, approximately .002 % of the “Glee” viewing audience chuckled: me, and some dude in Fairfax County, Va. who still has a poster of Joe Jacoby on his wall.

But that’s not important. What’s really important is how “Glee” plans to handle its production of “Grease.” Or, as they’re calling it, “Glease.”

Much like last season’s “West Side Story”production, the audition process for the Sandy-and-Danny saga was completed in a single episode (this week’s), and the show will be staged next week. (Look, everyone already knows the words to “Summer Nights.” How long do rehearsals honestly need to take?)

For those of you who currently watch “Glee” with one eye open — skipping some episodes and checking out the ones that seem more “significant” — here’s what you need to know about the Lima High cast of “Grease” before watching next week’s episode, which of course you will watch because as someone who cares at least vaguely about musical theater, you are required to care about all things “Grease.”

Blaine is not playing Danny.

Obviously this seems very wrong, but Blaine removed himself from Zuko contention because he’s still too distraught over his breakup with Kurt. He can’t take the pressure of being Kenickie’s second at Thunder Road right now, okay? So he opted to be the Teen Angel and sing what will surely be a swoony version of “Beauty School Drop-out” to Sugar, who was cast as Frenchy. In the meantime, he got to make every expression on the sad-face spectrum while performing “Hopelessly Devoted to You.”

Wade/Unique is playing Rizzo.

This was a huge plot point this week because Sue Sylvester is completely opposed to a boy who gender-identifies as female playing a girl who gets knocked up by Kenickie. (Who, for the record, will be played by Sam.) But we knew all along that Unique would be cast as Rizzo despite Sue’s opposition because “Glee” is about acceptance, and also about staging a moving and meaningful version of “There Are Worse Things I Could Do.”

Marley is Sandy.

Because she’s sweet and innocent but can still pull off hot pants. Plus she and Unique did a spirited version of Pink’s “Blow Me (One Last Kiss),” which really should take the place of “Look at Me I’m Sandra Dee (Reprise)” but probably won’t.

The new guy, Ryder Lynn, is Danny.

(Mike Yarish/Fox)

Blake Jenner, winner of the most recent “Glee Project,” stepped into his role as Ryder, the sophomore football player who has no performance experience yet was miraculously able to knock Foreigner’s “Jukebox Hero” out of the park when Finn forced him to get onstage. Which was just unbelievable. There’s no way any contemporary teenager would know the words to that song.

Anyway, he got the lead, allowing Marley to have another potential suitor, and Finn to have a young student who reminds him of himself and, therefore, will help him reconnect with his inner Finn-ness once more.

Why the guy has a name that’s oddly reminiscent of Zach Levi’s character in “Tangled,” however, remains a mystery.

Tina Cohen-Chang once again plays second fiddle.

Remember last season when it seemed like Tina would finally get her chance in the sun once Rachel graduated? Well, not so much. She was so annoyed by ex-boyfriend Mike’s presence that she didn’t even try out for the big parts and is now, therefore, stuck being Jan. Start practicing your toothbrush jingles, girl.

Brittany was miscast as Cha Cha.

Granted, she can pass for the best dancer at St. Bernadette’s. But she doesn’t seem quite ... hand-jive-evil enough.

The increasingly hard-to-stomach Kitty should have been Cha Cha.

Kitty — otherwise known as Meaner, Non-Latina Santana — proved her Cha Cha chops during the particularly contentious audition process. But instead of landing that part, she was placed in the role of Patty Simcox. Who is the bad seed of Rydell High. So maybe this actually makes sense.

And there you have it. So during the next seven days, get your overhead lifters and your four-barrel quads and prepare yourself for “Greased Lightning,” “Glee”-style.

I refuse to call it “Gleased Lightning.” Re-fuse.