Cristina is back! She's back and she's awesome! Unfortunately Owen can barely manage to speak two words to her, but there will be time to figure that out. She's totally impressed that Mere is now Medusa but tries to get some of her own street cred back by giving her interns Smash and Heather unflattering dwarf names. The new head of cardio is too busy to bother with teaching her or even to really work with her at all and instead basically gives her free rein to do whatever she wants to. The first patient she sees needs immediate emergency surgery and she has Smash and Heather scrub in which makes them go from hating her to loving her; then once they are inside the OR, it turns out she's become a pretty great teacher in her own right. They save the guy's life but after the surgery Owen chews her out for doing this massive surgery on her own without a consult from her new boss, Dr. Russell, and suspects she's going to be fired when he finds out what happened. Actually, though, Dr. R is super pleased with what she did, thanks her, and then tells Owen that he can see why he fought so hard to have Cristina hired back. Aaaawkward, since Cristina had assumed from Owen's distant behavior that he didn't actually want her back there and she'd just confronted him about it. So the I love you/I can't be with you dance between these two begins anew.

Mere has made a deal with Alex to sell him her old house but when he comes to her with a list of cosmetic repairs she needs to make she refuses since they already made a deal. The two argue all episode long until finally she explains the story behind each of those blemishes and how much they mean to her. Alex decides it's all cool and he'll take the house as-is, so they shake on it. He's shocked when he gets to his new home for the first time and finds Cristina settled in on a makeshift bed in the middle of the floor. She can't handle all of the memories at the firehouse so she asks Alex if she can be his roommate. After he gets in a good gloat about Cristina finally needing something from him, he agrees to let her stay.

Oh, and they are totally still setting up some sort of coupling between Alex and Princess Kate. She spends the episode trying to figure out what is wrong with a homeless man who regularly shows up to vomit on the doctors but whose tests are always negative. Kate cleans the guy up so he looks presentable and teaches Owen an Important Lesson about giving equal care to everyone. Of course it turns out that he does have some very rare and hard to diagnose condition; at the same time she finally earns some respect from Alex and maybe starts to think he's not as bad as she first thought either.

April and Jackson are still hooking up but each time they finish, April immediately starts beating herself up and talking about what a horrible thing they just did. Jackson is sick of listening to this and finally just walks out to avoid her. His mood isn't helped when he accidentally gets a saucy email from Richard that was meant for the other Avery in Richard's address book and then after forwarding it to his mom, accidentally gets her saucy response. He yells at Richard a couple of times about it but Richard finally points out that he thinks Jackson might actually be okay with his mom finding someone since most people who get an email intended for someone else just delete it or reply without reading the entire thing and forwarding it along. Jackson tries to deny it but it seems quite true and then somehow inspires him to go tell April that he has feelings for her. She's pretty delighted and so sorry for hurting his feelings, but he manages to run off before they can sleep together and he has to hear more of it again.

Bailey had a young patient who she can't diagnose, and she tells Callie that she wants Arizona back so that she can get back to work and help with cases like these. Callie just reports that Arizona is still prickly and mean and is best left alone. She's having a hard time on her new prosthetic because she's not using it perfectly right off the bat so she won't leave the house with it and she's still taking her frustration out on Callie. Bailey decides to get sneaky and push Arizona without her knowing it to see what happens. She calls and asks for advice on the patient, telling Arizona she'll have the chart dropped off at the house, but never actually has it sent over. Arizona has to get out of bed, put on her leg, and walk to the door; when the chart isn't there Arizona stays up waiting for it and doing some annoyed pacing, which turns out to be decent practice. She finally gets so fed up with waiting that she goes to the hospital, which Callie sees but Bailey shoos her away so that they don't spook Arizona too badly. Bailey never says a word about the leg but does get Arizona's help in diagnosing some rare disease in the patient and Arizona looks happier than she has since before the crash.

Speaking of the crash, the lady lawyer is back with a couple of additional lawyers in tow and they need to do interviews with all of the victims to find out just how hurt they all are so that they can figure out what amount of money they can try to get. No one really wants to have to think about the full extent of their injuries and losses but they all eventually have to, other than Cristina who keeps trying to brush them off but finally admits to a bit of PTSD. Callie and Derek have to do an interview together where the lawyer pushes for Callie to admit that Derek's probably never going to operate again. After lots of pushing, Callie admits it. She then has a confrontation with Derek where she yells at them for pushing them into this rather than just taking the other settlement and pushing her into doing his surgery. To his credit, Derek takes responsibility for that bit and doesn't blame her. Once she sees Arizona up and about, though, she recants her statement and suggests all sorts of other things they might try that she was too scared to suggest before. Even so, the lawyers determine that the amount of money they deserve is a colossal sum that is beyond what the charter company could ever pay so they think it's best to go after the hospital that put them on the plane in the first place: Seattle Grace Mercy West.