Meredith tells Alex and Maggie that a woman answered Derek's phone. Meredith tries calling Derek, but it goes to voicemail. Meredith ends up telling Alex, Maggie, and Callie that Derek has done this before: when he left Addison for her. Callie tries to reassure her that everything is okay and that she's Team MerDer. At the end of the episode, Derek comes back and begins to explain why he rushed home to see her.
A driver believed to have Alzheimer's gets into a car accident with a musician and his pregnant wife. It turns out to not be Alzheimer's. Richard thinks that Maggie doesn't know about having the Alzheimer's gene. At the end, she tells him that she's known for a long time. The pregnant woman dies, but they are able to save the baby. Jo gets very emotional over the whole ordeal. Bailey tells Jo that caring deeply for her patients is what is going to make her a great doctor.
Arizona sees Callie kiss a woman. Arizona appears to be jealous, and Callie doesn't want to hear anything she has to say. Turns out Arizona wasn't jealous. She just wanted to warn Callie that she had dated that woman once and she was crazy.
Jackson finds April's behavior to be strange. She tries to have sex with him in the closet, but he would rather talk about her behavior. April is mad at how he's treating her with kid gloves. She just wants to be herself again. They end up having sex in their car.
Owen and Amelia keep trying to hook up in the on-call room, but they continually get interrupted.