On Meredith's last day at Grey Sloan, doctors plan a goodbye surprise while Nick confronts her about their future. Interns compete to scrub in on a heart transplant, and Richard asks Teddy an important question.
Teddy makes a challenging decision; Maggie and Winston aren't on speaking terms; Link leans on Jo for emotional support as he preps for a surgery on a well-known athlete; Simone and Lucas are surprised by an unlikely visitor.
Simone is met with a life-changing decision upon the return of someone from her past; Blue and Jules shadow Maggie on a risky case; Jo and Link tend to a pregnant woman; Lucas and Mika throw a party filled with surprises.
Catherine returns to Grey Sloan for a surgical case that makes Lucas and Blue queasy; Amelia treats a patient with a family that's a little too supportive; Owen takes his medical future into his own hands, much to Teddy's surprise.
Addison makes a special appearance at Grey Sloan to welcome Bailey's new OB/GYN trainees. Maggie's lung transplant is derailed, and Nick bonds with Lucas - before the day takes a shocking turn.
In the immediate aftermath of shocking events at the clinic, the hospital goes on lockdown and the Grey Sloan doctors split up to save multiple lives; Maggie lands in hot water with Winston; Jules' roommate makes a surprise appearance.
A bull rider shows up at Grey Sloan with severe injuries, forcing Maggie, Amelia, Owen and Blue to examine their own biases; Simone can't find anyone to be her maid of honor; Mika takes drastic measures to pay down her student debt.
Amelia takes her personal problems out on her work colleagues, and the threats against Bailey come to a terrifying head. Lucas and Jules make a risky decision on a patient, and Mika struggles with burnout
Teddy calls an emergency meeting to discuss the intern program; Link wrestles with his own self-doubt as he preps for a massive surgery; Nick shares some much-needed guidance with a struggling Lucas.
Richard and Teddy make an exciting announcement; Jules and Blue butt heads over Maxine's care; Lucas helps an artist decide on a risky procedure; Jo and Mika tend to Sam; Simone faces a life-changing decision.
Simone's wedding day arrives as Jo and Link's relationship hits a major turning point. Meanwhile, the attending surgeons fly to Boston, forcing a reunion between Nick and Meredith.