William, a heavily guarded death row patient, arrives at Seattle Grace with a serious stab wound. His presence amps up the tension between Cristina and Meredith, who still aren't talking. It also causes a rift between Meredith, who is sympathetic to the patient's complaints of severe pain, and Derek, who takes offense when William tells him, "We're not that different you and I. People are alive when they meet us and then it all changes somehow."
William's X-rays reveal that a piece of the homemade knife is still in his spine and he needs an operation, even though he's scheduled to be executed the following week.
Witnessing the animosity between Meredith and Cristina as they argue whether William deserves their care, a puzzled Owen tells Derek, "I thought they were friends." "They were," says Derek.
George catches Izzie talking to Denny, which she calmly explains by saying she likes to "think out loud." Since Alex told her he loves her, she decides she has to tell him the truth about Denny. "Tell him I said, hi," Alex says, shrugging it off.
George asks Lexie if she's ever coming home and she tells him, "Rent the room."
Mark tells Lexie that she was "fantastic," but that "It can't happen again and no one's going to know about it." Seeing how Mark tries to avoid Lexie, Callie figures out that he slept with her. "Only once," Mark says, explaining how Lexie "violated him with her nakedness," and he couldn't refuse. Callie tells him that he should be a professional, but then loses her cool when Sadie flirts with her.
Miranda tells Alex to take special care with a boy, Jackson, whom she's been helping treat for three years. The boy's long-term doctor, Dr. Kenley, collapses with a heart attack as he's examining the boy. The chief takes the news of Kenley's death hard and retires into his office, with a huge "Do Not Disturb" sign on the door.
A young female doctor, Dr. Arizonan Robbins, takes over Jackson's case and dismisses her late colleague's approach as outdated, much to Miranda's dismay. Once they open the boy up, Dr. Robbins is appalled by the condition he's in and says, "This boy should have been on a transplant list a year ago. It's a miracle he's still alive."
Miranda goes to Richard to complain and he points out that Miranda's never approved of any of the attendings and that Robbins graduated at the top of her class. "Deal with it," he orders her.
Miranda begs Derek to go talk to the Chief. "I'm not worried about Kenley dying or me dying," Richard tells Derek. "I'm worried about my hospital dying." He laments that he can't keep a cardiac surgeon and can't find anyone to replace Kenley. "I failed at the one thing I spent my whole life, doing," he says, insisting he's going to stay right where he is.
Miranda demands a second opinion after Dr. Robbins insists they put Jackson on the transplant list, so Arizona gives her the name of a top surgeon at Johns Hopkins. Miranda is finally convinced she knows what she's talking about. When she admits as much to Richard, he agrees to look at the boy's file.
Meredith calls Derek "inhumane" when he refuses to give William more morphine. "Killing people is inhumane. Denying him painkillers is a judgment call," he answers. Cristina asks William what he did to get on death row and he tells her and Meredith that he slit several women's throats, for "fun."
Cristina starts to vent to Owen about Meredith, but he brushes her off. When he offers to go out for a beer later, she say she's tired of the hot and cold routine and to "just leave me the hell alone."
Sadie sees that Meredith and Cristina are still not talking and reminds Meredith, "We had a fight like that once," and that their friendship was never the same afterward because Meredith "froze her out." She advises her not to let that happen with Cristina.
Mark and Callie obsess over their intern crushes together. Callie proposes they start their own recovery program, the first and only step of which is "Don't get naked with an intern." But that night at Joe's, Mark falls off the wagon and leaves with Lexie. "Damn, damn, damn," Callie swears when Sadie glances her way. Instead of going over to her, Callie orders another drink.
Izzie tells Alex more details about Denny: That she sees him all the time and the two even have sex, but Alex is okay with her having a "fantasy," even if it's not about him. Alex bakes a cake for Izzie's birthday and tells her to make a wish. She says she already has everything she wants, so he advises her, "Then wish that everything stays the same."
When Derek gets home, he tells Meredith why he was so angry about the death row inmate: two men killed his father because he wouldn't give up his watch. "As doctors, we're supposed to treat everyone the same, but they're not all the same." He says he wishes he could make things better between her and Cristina and wants to know what Cristina would do to cheer her up in this situation. "She'd turn up the music up really loud and make me dance it out with her," she answers, so that's just what he does.