News of Meredith and Derek's unsteady relationship raises a red flag for Zola's adoption counselor; Alex quickly realizes that he has become the outcast of the group after ratting out Meredith; and Cristina makes a tough decision regarding her unexpected pregnancy. Also, Chief Webber brings Henry in for a last minute surgery, alarming Teddy.
While Derek prepares to operate on a tumor deemed entirely inoperable, Hunt pressures Meredith to declare a specialty. As Cristina and Teddy try to steal a prized cardio surgery, the doctors celebrate Richard's 10,000th surgery.
On Valentine's Day Lexie volunteers to watch Zola for Meredith and Derek; Callie plans an evening for Arizona; and Ben shows Bailey how much he cares. Meanwhile, Christina and Owen drift farther apart despite the fact that he saves her when a car crashes into the hospital. Meredith and Bailey treat a woman who has headaches and seizures. Webber and Lexie treat a man who was hit by a car during a fight with his girlfriend. Alex treats a 10-year-old girl who has a severe reaction to peanuts when her boyfriend gives her a Valentine's Day gift.
In a final attempt to save Erica's life, Amelia arrives at Seattle Grace to beg Derek for help with the gliosarcoma case; Cristina and Owen engage in heated arguments during marriage counseling; Alex realizes that in order to be a good doctor, he'll need to improve his people skills; and Meredith is given a chance to shine when a man enters the ER after getting his hand stuck in meat grinder. Meanwhile, the residents continue to study for their upcoming oral boards.
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 for intern Morgan's premature son; and when Jackson snaps at a patient, Mark encourages him to find ways to relieve his stress. Meanwhile, Cristina lets her suspicions get the best of her.
Derek encourages a hesitant Meredith to work with him again in neurology; Jackson's mother, Catherine Avery, returns to Seattle Grace with a urology fellow and develops an interest in Richard; and Cristina becomes increasingly suspicious of Owen's every move. Meanwhile, Alex tries to deny the fact that Morgan may be falling for him.
A pet lion on the loose gives the hospital some fierce injuries to deal with. Meanwhile, Cristina continues to ignore Owen, Lexie reconsiders her feelings for Mark, Callie has to face Arizona's romantic past with other hospital staff, and Alex starts to feel uncomfortable about his relationship with Morgan.
Grey, Bailey, and Webber work on a multi-organ transplant but run into some barriers when Dr. Sloan, the temporary Chief, orders them to cancel the surgery. Meanwhile, Cristina and Owen spend the day at home, working through their marital problems.
While the hospital becomes the center of attention as the victim of a famous kidnapping case is brought to the hospital, the fifth years take their placement interviews. Meanwhile, Adele Webber's memory continues to deteriorate, forcing Richard to reconsider their relationship.
As the fifth-years head off to San Francisco to take the most important exam of their lives there are some surprises along the way; Owen and Teddy continue to fight back at the hospital; Mark and Lexie reconnect; and Tommy's condition worsens.
Six hours after their oral boards, the fifth years relive their answers and worry about their chances. Back at the hospital, Bailey has to woo potential candidates for the hospital and Mark is startled when Julia makes a proposal about their future.
Before the Seattle Grace doctors head to Boise to take part in an operation on conjoined twins, the Attendings pressure the 5th years for final decisions on their posts next year. Meanwhile, Arizona must face the reality of her friend's condition and Ben tries to get Bailey to go on a special lunch date.