Seattle Grace is in lockdown!
A death-row inmate is admitted after being stabbed in the spine with a makeshift knife. The Chief assigns Owen, Cristina, Meredith and Derek to the case. Sounds like the makings of a great double-date! Too bad Derek and Owen don’t see eye-to-eye and Meredith and Cristina aren’t talking. Oh, and the guy’s a sociopathic serial killer. On second thought, worst double-date ever!
To make things worse, Mer-Der have completely different views on how to treat murderer William Dunn (guest star Eric Stoltz in a very creepy performance). Meredith is sympathetic for the man since he’s going to be executed in a few days, but Derek can’t muster any compassion for a cold-blooded killer.
George catches Izzie talking to Denny. She calmly explains that she likes to "think out loud." Izzie decides to tell him the truth about her conversations with Denny. After all, Alex did tell her he loves her. But Alex blows off Izzie’s confession about Denny by saying, "Tell him I said, hi." Dude, come on. Your girlfriend is fantasizing about her dead ex-boyfriend. You should be telling Izzie about all the things you have that Denny doesn’t. Like a pulse!
Mark is absolutely smitten with Lexie, but he’s trying to be strong because Derek has forbidden him from going near her. Callie, meanwhile, has her own growing intern-crush on Sadie. They form a support group, but it doesn’t last the day as Mark gives in to temptation later that night.
Miranda tells Alex to take special care with a boy, Jackson, whom she's been helping treat for three years. Things take a bad turn though when his long-term physician, Dr. Kenley, keels over from a heart attack.
A young female pediatric surgeon named Arizona Robbins takes over Jackson's case. Dr. Robbins dismisses her late-colleague's approach as outdated. Once they open the boy up, Arizona is appalled by his condition. This sends Bailey running off to the Chief in frustration. But Richard’s not having it. His hospital is coming apart at the seams and it’s all he can do to hold it together.
Sadie sees that Meredith and Cristina are still not talking. She reminds Meredith that they had a fight like that once and their friendship was never the same. Meredith "froze her out." She advises her not to let that happen with Cristina.
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. Derek says, "As doctors, we're supposed to treat everyone the same, but they're not all the same." Okay, now we get his pain.
Derek says he wishes he could make things better between her and Cristina. He wants to know what Cristina would do to cheer her up in this situation. Meredith tells him the truth: she’d crank up the music and they’d dance it out. Finally, we get to see some McDreamy dance moves as he cranks the stereo and, well, they dance it out.