While Meredith faces the repercussions of messing with the medical trial, April tries to step up at Chief Resident; Cristina and Owen disagree.
Meredith and Derek's relationship concerns Zola's adoption counselor; Alex notices he has become an outcast; Cristina makes a difficult decision.
Four junior officers endure a series of challenges while they are evaluated for possible promotion; one of them faces a dangerous mission.
The team are forced to act fast when a ransomeware attack paralyses the city. Sam prepares for his and his family's first Christmas since his wife's death.
Artie tests positive for an STD and must tell his sexual partners. Blaine's weight gain causes issues with Kurt.
