Tonight is the night we’ve been avoiding for months: Our last episode with Cristina Yang (Sandra Oh) and the last episode of Season 10. Too many goodbyes for our taste, but at this point, they’re inevitable… and after tonight, Grey’s Anatomy as we know it will never be the same.

Obviously something cataclysmic is about to happen to our favorite hospital (was there ever any doubt?), and we expect it to be a very emotional evening. Get your comfort snacks ready and plenty of tissues by your side — it’s going to be a long night.

Missed the emotional torture the first time around? You should probably watch the episode for yourself, but in case you’re looking for a heads up, here’s what you need to know about tonight’s Grey’s (Season 10, Episode 24: “Fear (Of The Unknown)”):

It’s Cristina’s last day at the hospital, but first, she’s gotta hit the mall to pick up a few things before she boards her plane to Zurich to go claim that hospital! She and Owen have been gettin’ it on in the trailer (so predictable), and Cristina has to get a scheduled heart transplant done today. Loose ends (and ventricles) must be tied before she goes all Swiss on us!

Meanwhile, our big disaster has struck: A massive explosion in a mall, resulting in tons of casualties and injuries. What caused it? Was it a chemical attack? Was it terrorists? Nobody knows for sure. Either way, Owen holds a press conference as the hospital fills with patients.  Homeland security is on the scene, and there is blood pretty much everywhere. Grey Sloan Memorial is not where you want to be right now. Wait...wasn’t Cristina at the mall? Yes. She was. And now she’s dead.

Just kidding! Shonda promised she wouldn’t do that to us! Don’t worry — Cristina never made it to the mall. She’s fine. Although it is absolutely imperative that she gets this heart transplant done. Nothing in Seattle is finished business, and she has to finish something.

But Meredith isn’t having it. She puts Cristina in a cab and off she goes. Toodle loo, Yang!

Catherine Avery is in the hospital, helping with the aftermath of the explosion. Richard isn’t too thrilled to see her, though. Aaaand neither is her beloved daughter in law, who just so happens to run into her in the middle of both the supply closet and a nervous breakdown. How can April raise a baby in this world when terrible things happen every day?

You don’t let the fear get to you, Catherine advises. They hug it out, and there may actually be hope for these two after all. All together now: Aww.

P.S. About that whole mall catastrophe… Yeah, it wasn’t terrorists. Just your run of the mill gas main explosion. Homeland security leaves with their tail between their legs after giving Meredith way too much sass. Take that, Agent Zero!

Cristina’s back, because she needs to finish something. Not her weird relationship with Owen, and not her heart transplant surgery. Nope, she’s gotta give Meredith a proper goodbye, and in this instance, that means dancing it out. And they do so with such grace and coordination. God, we love these two.

When Cristina leaves for real, she takes Shane with her. In a surprising turn of events, Shane has demanded that he get to follow his teacher so he can keep learning. And Cristina, as someone who’s definitely been in that position a time or two, quickly agrees. See you guys in Zurich!

Oh, and Leah? She stormed out of the hospital after being disrespected one too many times, presumably never to be heard of again. And frankly, we can’t blame her.

There are two more explosions left in this episode, though, and the first one is the marriage between Mr. and Mrs. McDreamy. Thanks to a little pre-departure reminder from Cristina, Meredith has decided to stay in Seattle, presidential job offers be damned. Derek has always thought his career was more important than hers, she screams at him in the Dreamhouse kitchen, and this time, she’s putting her foot down. And why shouldn’t she? Derek’s been really unfair to her this season, and she shouldn’t have to compromise yet again.

Earlier in the episode, Bailey was pissed because Jackson cut funding to her genome project. Later in the episode, Bailey gets decidedly un-pissed when Richard tells her he’s recommending her for Cristina’s vacant spot on the board. Yep, Bailey will be calling the shots, and first order of business? Reinstating her funding.

 Except for the fact that Cristina — after a heartfelt chat — actually left her spot on the board to Alex, and he looks pretty darn jazzed about the idea. After all, the private practice hasn’t been too fulfilling, and this position could give him the money and prestige he’s been hoping for. So, yeah, this is definitely going to be an issue come fall.

And for the next explosion. You know, the one we totally didn’t see coming? The new head of cardio that Cristina hired is in Seattle because her birth mother was a pretty prominent surgeon at Grey Sloan back in her day. And, as she confides in Richard, her famous mom gave her up for adoption as a baby, but she does know her name. It’s Ellis Grey.

Boom. How do you like that for a cliffhanger?


Dan Clarendon is an assistant editor at Wetpaint Entertainment. Follow him on Twitter and Google+!