Credit: Adam Rose/FOX ©2012 Fox Broadcasting Co.

UPDATE: To read the promo analysis for next week's Season 4 finale, click right on over here!

We have good news, and we have bad news. The bad news is this: There will be no more
Finn for the rest of Season 4. Actor Cory Monteith checked into rehab at the end of March, so he will be missing from both Episode 21, and Episode 22 — the Season 4 finale.

Now for the good news. Next week’s Glee Season 4, Episode 21: "Wonder-ful" looks like it’s going to be fantastic. Plenty of familiar faces are returning, and we had no idea how much we’ve missed them.

The promo for next week’s episode has plenty of clues about what’s in store. We’re breaking the whole thing down — second by second, frame by frame — hunting down as much info as we can find. Here’s what we’ve been able to uncover so far.

Credit: YouTube Photo: Glee 4x21 Promo, "Wonder-ful" — Is Blaine Proposing to Kurt?!

00:01 — It’s a Wonder-ful new Glee.

What? you say. Aren’t all Glee episodes wonderful? Perhaps. But this particular episode will be even more so than most. It’s an entire tribute episode dedicated to the music of Stevie Wonder.

00:03 — Mercedes returns to McKinley!

Oh Mercedes (Amber Riley), you have no idea how much we’ve missed you... and your powerhouse vocals. The sassy songstress returns from L.A. to pay the kids at McKinley a visit, and she’ll be singing Stevie’s hit, “Superstition,” along with Blaine (Darren Criss) and Marley (Melissa Benoist).

00:06 — “Old friends are back.”

Look at that! Mike (Harry Shum Jr.) has come to visit McKinley, too. He made the trip over from Chicago, while Kurt (Chris Colfer) is home from New York City. Of course, they’re here to lend a hand in the choir room. “Your teacher begged me to come here and be your new vocal coach,” Mercedes informs them.

00:10 — “Old flames are reunited.”

Sorry... we would write something about this, but the sight of Kurt and Blaine smiling and holding hands adorably just sent us into a hysterical fit of pure excitement and happiness. We’ll get back to you in a day or so. CAN’T EVEN FUNCTION SQUEE!

00:11 — Blaine has some BIG news for Kurts dad.

Aww, aren’t Blaine-Burt (Mike O’Malley) scenes just the cutest? Burt’s buttoning his shirt. Blaine’s standing there timidly. “I would like to ask Kurt to marry me.”

WAIT... WHAT? Is it’s even possible, we’re pretty sure we’re functioning even less than we were a second ago. This revelation is potentially the greatest thing we have heard in the entire history of Glee

Sadly, Kurt’s dad doesn’t seem to be reacting with as much excitement to all of this as we are.

00:17 — “Old battles reignite.”

Oh hai, Kate Hudson. You’re pretty. But would you mind going away for just a second? Burt was just about to tell Blaine whether or not he has his blessing to propose.

00:19 — Rachel starts pleading with Cassie.

“I cannot miss this callback, okay? This is a once in a lifetime opportunity.” Cassie stares at her for a moment, then gives a huge, devilish grin. “And I’m going to be there to watch you blow your first big Broadway audition.

Well, as long as she lets her go, right? Small victories. And speaking of victories, can we take a moment to talk about how perfect Cassie’s abs are? The NYADA teacher will be singing and performing Stevie’s “Uptight (Everything’s Alright),” and we bet her abs will look ridiculously flawless the entire time.

And can we take an additional moment to talk about what Glee didn’t show in this promo? Episode 21 will introduce Artie’s (Kevin McHale) mom — played by Sons of Anarchy actress Katey Sagal. What’s more Kitty (Becca Tobin) has decided to tag along. Now that Ryder (Blake Jenner) has rejected her advances, we have a feeling she might just follow up on that love connection with Artie we first saw hints of a few episodes back. Watch out, Jarley. We just might have a new McKinley power couple on our hands!