Derek chooses Alex Karev as his resident instead of his wife, Meredith Grey , arguing that their personal connection and Meredith’s family history (her mother, Ellis) would make it too emotional.

Following the bombshell that is pregnant with Mark Sloan's baby, the trio struggles to navigate their new reality.

Mark finally confesses the pregnancy to Lexie Grey . Lexie, feeling like Mark is starting a second family without her for the second time (referencing his daughter Sloan), walks away from the relationship.

The episode features a heartbreaking case involving a trial participant, Daniel Cobb, who mistakes his wife for another woman he met at an assisted living facility. The Pregnancy "Hormone Casserole"