We jump back to the days of the plane crash. A rescue team transports our favorite docs from the woods. Meredith freaks out in a hospital. She's looking for Derek. She's looking for Lexie. Mer calms considerably when Richard and Bailey show up with Zola in hand. Later, she visits Cristina, who seems to be in a catatonic state. All of the injured docs are sedated as they are transported home on another bumpy plane ride.
Time passes. Derek and Meredith argue about moving to Boston. She can't even think about that right now. He's wondering if they'll still want a surgeon with a hand that's only at At work, Meredith tries to keep her colleagues positive. She insists that Mark will come out of his coma and Arizona won't lose her leg. She states this emphatically as Jackson checks up on a still-catatonic Cristina, who is kept in bed with restraints. Meredith begs her to say something. It doesn't happen.
We flashback to rescue day. Derek tries to tell the doctors treating him that he's a surgeon as they try to salvage his hand. Callie does follow-up work but the nerve damage that was done is what gives him that number. Derek may never operate again. That doesn't stop him from trying to talk another surgeon through a tricky procedure using his approach. It doesn't go well. Mark gives his pal a pep talk reminding him that he loves a hopeless case. That's why Derek talks Callie into performing a risky nerve graft surgery that could get him to gaggle of interns make snide comments about Cristina outside her hospital room. This prompts her to grab a vase full of flowers and heave it toward the window. SMASH! The interns scatter. Cristina still isn't talking, but it's obvious she's been listening. Owen vowed that he would be there to help her after she was pulled from the woods. Cristina tells him that she stayed awake for four days enduring horror. This prompts her to flee to Minnesota, but not before parting acrimoniously with Meredith.
Amputation seems to be the only option regarding Arizona's leg. She refuses to accept this. Back in Seattle, Alex tries to apologize for all that's happened to her. It doesn't go well. Arizona only got on that plane because she was totally ticked at him. She spent a lot of time wondering why such a horrible thing happened to her and not to someone like him. Later, Arizona makes Callie promise that she won't let anyone cut off her leg.
Mark kept dying during the rescue, but they kept bringing him back. He survives to tell Julia that he loves Lexie. He "loved" Lexie. A short time later, Mark's health improves dramatically. Richard thinks it may be "the surge." That's when terminally ill patients have a final burst of energy followed by epiphanies. Sadly, he's right about this. Mark knows it, too. That's why he tells Richard that he wants all care to be withdrawn if signs of recovery are not seen after 30 days.
Arizona crashes just as Callie operates on Derek's hand. Alex needs consent to cut off her leg to save her life. Callie has no choice but to give it to him. Meredith offers to help with her husband's operation. Callie assures her that she's fine. As Meredith watches the rest of the operation from the observation room, she leaves a voicemail message for Cristina. A lot of bad things have happened to her in Seattle, but so many wonderful experiences have shaped her life there as well. Cristina calls back to assure Mer that she will always be her person.
Lots of things are happening as Mark Sloan slips into the coma from which he will never awaken. April stuck around for awhile, but ultimately headed back home. She and Jackson didn't really have a chance to say goodbye. Alex amputates Arizona's leg while Callie completes Derek's surgery. Richard is by Mark's side as he takes one last breath before crashing. We already know what happens after this and we're all still heartbroken by it.