Amelia arrives at Seattle Grace to beg Derek to help with a case.
Callie surprises Arizona with a romantic evening.
Meredith dreams of what her life would have been.
Richard's 10,000th surgery is a liver transplant for two sisters.
The doctors form two teams to operate on conjoined twins.
Teddy asks Cristina to help with an O.R. patient.
Teddy is called away on another case, as Henry is brought in for surgery.
Jackson's suspicions about Mark and Lexie interfere with work.
Owen organizes a baseball game against Seattle Presbyterian.
Meredith tries to get Derek interested in a patient's rare brain tumor.
The residents try to impress Jackson's mother, Catherine Avery.
A stampede at a comic book convention leads to an influx of patients.
The chief makes a decision that shocks everyone at Seattle Grace.
Meredith and Derek's relationship concerns Zola's adoption counselor.
Meredith faces the repercussions of messing with the medical trial.
Shockwaves rock Seattle Grace this season. Will Alex reveal Meredith's hand in the tampering of a major medical study? Loyalties will be tested, relationships will be strained and everyone's future will hang in the balance.