Sadie, who's staying with Meredith, asks her, "What do you think of your sister, Lexie, as my new BFF?" "I don't see that," cautions Meredith. "She was raised right, with parents and rules, and smiley-face posters on her wall."
Sadie joins the interns, who've just given Cristina's "Number Two" intern an epidural. "I'm impressed. Deth was so wrong about you," she tells Lexie, adding, "She thinks your a priss."
Stung by the criticism, Lexie suggests that they take out the sedated intern's appendix. Sadie says they can "be in and out of an O.R. before anyone notices." The intern objects to being operated on, so Sadie volunteers.
Izzie tells herself she's only imagining Denny, but to prove he's real, he makes love to her. Meredith overhears the noisy lovemaking and assumes Izzie is with Alex, until she sees Alex in the hall. Alex offers to join Izzie, but she says she's feeling sick and is going back to bed.
A patient knocks Callie to the floor, breaking her nose. She laments her run of bad luck to Mark, who assures her he'll still be her friend who sleeps with her, after her nose heals.
Lexie has second thoughts as she's about to make the first incision on Sadie. "This is a really bad idea," she says, "This is a very stupid thing, a thing I'm sure we will all regret, possibly from jail." But Sadie, who's under a local anesthetic, makes the first incision herself. When it appears her appendix is inflamed, one of the interns says they should call a resident, but Sadie refuses, telling her, "If you can't handle it, leave!"
The surgery on Sadie goes terribly wrong and all the interns bail, leaving Lexie to beg Meredith for her help. She and Cristina are shocked to see Sadie open on the table in the outpatient room. The intern who's been left in charge says, "I think she's dying."
Cristina and Meredith take over, but insist on sending for Miranda, who talks Cristina through the surgery. When George hears about it, he asks Lexie why she didn't come to him for help. "This wasn't about you," she tells him. "This is the one thing in the last few months that wasn't about getting you to notice me." She walks away and one of the interns tells George, "Dude, she's, like, in love with you. How did you miss that?"
Richard praises Cristina and Meredith for saving Sadie's life, but Lexie, who thinks the Chief is reprimanding them, bursts in to say it was all her fault and that Cristina had told her to "shut it down" the day before. "You knew about this yesterday?" Richard thunders. Meredith is even madder that Cristina didn't tell her about what the interns were doing, but Cristina snaps back, "You didn't have my back in that room. You have a relationship with the Chief, but you didn't say anything to defend me."
"Effective immediately, everyone here is on probation. So much as sneeze, and you're done," Meredith tells the interns. Alex says they've lost his respect and jumps on an intern who says, "You seem to still respect Izzie Stevens, and she killed a patient." "She was trying to save a man's life. You almost killed a friend for fun," Alex yells. "There's a difference."
Miranda tells Callie she envies the interns their enthusiasm and that her operations have become "rote" and "boring." "Maybe I'm just tired of it," she says and Callie says she feels the same.
Meredith chews out Sadie for her reckless behavior. "What the hell is going on with you?" she asks and Sadie admits, "I don't know."
Owen is finally prompted to act on his feelings towards Cristina. He shows up at her doorstep and tells her, "I think you're beautiful."
Derek asks Meredith to stop bringing home "strays" like Sadie, but after Lexie's disastrous day, he brings her back to the house, partly so that Mark doesn't hit on "little Grey."
Izzie tells Alex, "I'm a mess." His response: "I can handle the mess," and that he's not going anywhere. "I'm sorry, I can't," she tells Denny, who says he'll be "right here."