Derek has been spending his time in front of a roaring fire with Mere, thinking of how to cut out Izzie's tumor and thinks he's figured it out. The only problem is that there's a risk of also affecting Izzie's memories and personality, so she has a really hard time deciding what to do. She befriends Paris Geller, who decided against surgery and bought herself two unexpected years and seems to be doing great. That, and Meredith's ordering her not to have the surgery, makes her decide against. However, Paris then collapses and her surgery is unsuccessful and she winds up on a ventilator -- that, and a conversation with George where he tells Izzie she knows what she needs to do, makes her decide to do the surgery after all but to sign DNR so that she doesn't end up as a vegetable on life support if things go wrong. Alex is horrified, but Izzie convinces him it's the way to go, and he sobs and kisses her and sends her off to surgery. Meredith watches all this and realizes just how short life can be, so she asks Derek to go to the courthouse the next day, because she doesn't want to not be married to him anymore.

George, Callie and Hunt are treating Matt Saracen, who is a soldier back from Iraq and with chronic pain in his leg as the result of an injury. He knows already that there isn't anything they can do to help that hasn't already been tried, so he begs them to amputate his leg so that he can get a prosthetic and go back to Iraq. Callie thinks he is nuts and refuses, but eventually he's able to convince her to do the surgery. When he explains why he wants to go back (that is his real family there, his family here doesn't understand him, and he could make a difference and help people) something clicks in George's mind and he goes and signs up to join the Army himself. Hunt is also affected by what Matt says and decides that the reason he is having a hard time in Seattle and hasn't even called his mom is because he has unfinished business there. But when he tells Cristina, he seems surprised that she flat-out refuses to support his decision. She finally admits, after the end of a horrible day with what happened with Izzie and Paris, that she doesn't want him to die. This seems to finally click, and he decides to visit his mom, with Cristina by his side. And his mom is none other than Edna Harper, who seems to have moved to Seattle from Everwood.

In lighter storylines, the Chief is trying to keep Bailey interested in general surgery and woos her with the purchase of a fancy surgical robot. She's delighted and spends the day doing awesome surgeries and skipping around like a giddy child, and winds up skipping a surgery with Arizona to use the machine instead. Arizona sees what is happening and tells Richard she's going to beat him at this game, because she has joy on her side. Bailey realizes this to be true when she finds Callie and Swender both shattered after their respective days, and so she takes them upstairs so that they can watch Arizona tell a kid's parents that he is going to be okay, and that warms everyone's hearts so that they can get out of bed to do more surgeries. Oh, and Mark asks Lexie to move in with him and she totally shoots him down as it turns out she's got the next ten years of her life mapped out and apparently she can't reach her work goals if she's cohabitating with Mark, or something lame like that.

Check out part two of the finale here, then discuss both episodes in our forums. Then see vloggers Val and Beth debate the legality of the Izzie/Denny relationship in TV is the Answer!