Those Interns are causing trouble again! Frustrated that the Residents are too busy dealing with their own drama to actually teach them, the Interns have started practicing on the only subjects they have available -- each other! But Sadie, that brazen, British troublemaker, takes things too far when she comes up with the idea of removing each other’s appendices and even starts cutting herself open to get started! Lexie and the other Interns do their best to operate, but they quickly lose control of the situation as complications arise. Now things have gone from a crazy elective surgery to a matter of life and death.
Izzie tells herself she's only imagining Denny, so she does what any rational woman would in her situation—she makes love to the hot ghost Denny. Wait, what? You read that right, we’re talking about SUPERNATURAL SEX. Seeing your dead boyfriend is one thing, but actually getting down with him is something else. Her fantasy love-making is so loud Meredith overhears 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. If Denny was there, wouldn’t you?
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." Yeah, great diagnosis there.
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 and she unloads on him for being so blind to her advances. It takes one of the other Interns to break it to George that Lexie has been pining for him for months. When the Interns are cluing you into stuff, you know you’ve been out of it.
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 just as mad that Cristina didn’t tell her about the Interns, but Cristina is hurt that Meredith did absolutely nothing to defend her best friend in front of the Chief, especially considering Meredith was just as guilty of ignoring the Interns.
All of the Residents chew out the Interns for their reckless behavior, with one of them even having the nerve to talk trash about Izzie in front of Alex. He shuts the kid down, hard. But the damage has been done and Meredith and Cristina aren’t exactly on speaking terms after the incident.
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." You can swoon. It’s a swoon-worthy moment.
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."