As Adele’s condition continues to deteriorate, Richard considers altering their living situation; an explosion at a local coffee shop results in a busy day in the ER for the doctors; Callie takes Meredith under her wing by helping her study for her boards; Lexie joins Arizona and Alex in peds, as they continue to care [...]

Derek’s sister Amelia arrives from L.A. to ask Derek for help with Erica’s gliosarcoma; Cristina and Owen argue heatedly during marriage counseling; Alex realizes that he must improve his people skills to be a good doctor; and Meredith gets a chance to shine when a man arrives in the ER with his hand stuck in [...]

It’s Valentine’s Day, and Lexie and Mark draw babysitting duty (for Meredith and Derek, and Callie and Arizona, respectively). Meanwhile, Ben shows Bailey that he knows her better than she thinks; and the ER also fills with romantics, including a 10-year-old girl who has an allergic reaction to chocolates from her valentine; and a man [...]

Meredith dreams about what-ifs in flashbacks. Among them: Her mother remained happily with her father and didn’t get Alzheimer’s; she hadn’t met Derek in a bar, and he stayed with Addison; Bailey had remained as meek as she was as an intern; and Callie and Owen had become a couple long before she met Arizona.

Richard performs his 10,000th surgery—a liver transplant involving bickering sisters (Peri Gilpin and Nia Vardalos). Meanwhile, Adele Webber is found aimlessly wandering the streets; Derek and Lexie take on a supposedly inoperable neuroblastoma case; Teddy and Cristina try to steal a case from Alex and Dr. McQueen, countermanding Owen’s orders; and Meredith searches for a [...]

The doctors split into teams for a risky surgery involving conjoined twins. Meanwhile, Teddy questions Cristina about Henry’s surgery; Bailey enlists Meredith to be a buffer between her and Ben, who’s pressuring her to ratchet up their relationship; and Richard teaches Alex a tough lesson in the OR.

As the human wreckage from a serious auto accident preoccupies the doctors, Teddy (who’s unaware that Henry has died) calls on Cristina to help with a patient; and Lexie works alongside Mark’s new girlfriend, Julia, during an eye surgery.

Henry is sent to the OR for emergency surgery while Teddy’s away; Meredith and Derek receive news about Zola; Callie and Jackson are blamed for their patient’s post-op complications; and Meredith and Alex treat an ailing infant at a neighboring hospital and get involved in a life-threatening situation.

George’s mother (Debra Monk) returns to Seattle Grace after undergoing a botched surgery at another hospital, and the doctors wax nostalgic about George. Meanwhile, a harvested heart continues to beat outside its body; a new pediatric fellow excites Arizona and arouses Alex’s insecurity; Jackson allows his suspicions about Mark and Lexie interfere with his work; [...]

Owen tries to teach the doctors a lesson in teamwork when he signs them up for a baseball league; Lexie can’t hide her jealousy when she sees Mark with another woman; Alex fights to keep baby Zola from being transferred to another hospital because of a conflict of interest involving Derek and Meredith; and Richard [...]