The doctors face the consequences of the events that took place at April's wedding. Meredith feels betrayed when Derek goes back on a promise, Alex is furious after returning to the hospital and hearing the news about his father, and Arizona and Callie decide whether or not to move forward together. Meanwhile, Bailey realizes she was wrong about the motive behind Ben's decision to move back to Seattle.
Couples panic when the hospital announces a nonfraternization policy; Owen and Emma discuss the future; Meredith and Cristina have some girl time; Richard asks the residents for help with a rare cancer case.
Arizona's bad day escalates when she advises a patient on a potential double amputation; Derek breaks a promise; Stephanie and Jo find an abandoned baby; the nonfraternization rule leads to a suspension.
The doctors of Grey Sloan Memorial Hospital succumb to an infection that spreads like wildfire. Cristina deals with a complex case involving siblings and Alex begins to consider his future in the hospital.
Callie and Arizona discuss having another baby, Derek has a hard time juggling work and family, Jackson and April have their first big fight and Christina attends the Harper Avery Award Ceremony. But is she going to win?
The doctors work together to operate on two sisters joined at the head; Cristina travels to Zurich where she deals with a blast from her past; Richard voices his concern over the hospital's allegiance with the Harper Avery Foundation.
While Bailey faces dire consequences for her reckless behavior, Cristina interviews candidates for Dr. Russell's replacement. Alex returns with a motive, disappointment hits Callie and Derek brings forth a shocking proposal to Meredith.
Cristina must head to Zurich soon but she is unprepared to leave behind her life in Seattle. Fear runs amok throughout the hospital as an explosion in a shopping mall results in a mass casualty situation.
Callie and Arizona have to make a choice regarding surrogacy while the board has to decide whether to give Cristina's seat on the board to Alex or Bailey. Amelia overhears the truth about Maggie Pierce.
In this Maggie-centric episode, she continues to try to make a positive impression at the hospital but finds herself in extremely unfortunate situations. Meanwhile, Richard continues to hold onto his secret and the doctors work with a dying woman who is being kept alive by her daughter.
Owen introduces Callie to the Veterans Hospital patients in hopes that she will help them with her robotic limb lab, Jo becomes jealous of Alex and Meredith's friendship, and Maggie continues to confide in Richard. Meanwhile, Alex and Bailey prepare to go in front of the board.
Secrets from Ellis Grey's past come to light when Meredith watches old videos and reads through her mother's journals. Meanwhile, Maggie rocks the hospital with an unexpected announcement; Alex gets new responsibilities and Callie focuses her attention on the Veterans' project.
Callie and Arizona examine their marital problems and what's contributed to them. Meanwhile, Callie devotes herself to the veterans' project; Arizona strives to impress Dr. Herman; and Richard seeks guidance from Bailey.
A woman comes in badly hurt from a car jack and Owen pays some extra attention when she is found to have served in the military. Derek desperately tries to organize a dinner binding together Meredith's complicated family but is fought from every angle. Meanwhile April reacts strongly to the arrival of her mother and Arizona is fighting hard to manage under the pressure from her new "boss".
Arizona has to take care of one of Herman's patients. Everybody finds out Amelia was a drug addict and Derek lets her down. Jo has her first solo surgery. Maggie is invited to Ellis' house and Arizona decides to move in with Alex.
Pierce and Grey disagree with Derek about the best way to approach a patient's case, which lead the couple to a very big argument. Meanwhile Callie feels responsible for one of her veterans when he is pushed too far and a doctor's routine procedure shows devastating results.