Seattle’s favorite redhead returns and graces the Grey Sloan halls with her experience and expertise as she attempts to help Richard teach the newest crop of residents. Meanwhile, Meredith has a decision to make, and Link confides in Teddy.

The Grey Sloan doctors spring into action after an explosion rocks Seattle, with the incoming trauma hitting close to home. Owen experiences PTSD after he hears the explosion, while his sister Megan enlists help from Winston and Hayes in confidence. In Minnesota, Meredith and Amelia meet up with a familiar face who assists in their study.

The crossover starts on Station 19 S05E05 Things We Lost in the Fire (I).

A dinner party is thrown at the sister house in Nick's honor. Meanwhile, Grey Sloan Memorial receives a victim of a brutal hate crime.

It’s Halloween night at Grey Sloan Memorial. Meredith and Nick try to spend some alone time together; Levi is stressed due to overworking, and Winston and Owen have the interns practice trauma training on a real cadaver.

The attending surgeons fly to Boston, forcing a reunion between Nick and Meredith. Bailey gets a big surprise.

It's all hands on deck at Grey Sloan when a group of medical students is injured by a floor collapsing at their white coat party. Jo and Link are forced to talk about the future, while Jules confronts Winston about his attitude.

An unexpectedly complex case brings back painful memories for Simone. Jules and Blue make a high-stakes bet on who can finish their procedure log first. Richard suspects Winston is avoiding him.

Teddy and Owen plan a date night that gets derailed in more ways than one, while Jo struggles to do it all at home. Mika adds more to her plate to make up for taking time off to be with her sister, and Levi is faced with a monumental decision.

The doctors at Grey Sloan must put aside their emotions under intense circumstances. Levi asks James a shocking question that could impact their future.

In the midst of a deadly heat wave, the team at Grey Sloan struggles to keep up with an overwhelming amount of patients. Amelia and Winston face a challenging surgery, while Jo and Lucas run an errand for the hospital that takes an unexpected turn.

Bailey welcomes a renowned surgeon, whom she greatly admires, to Grey Sloan to help on a challenging case. Meanwhile, Teddy, Owen, Jules and Ben team up to save the life of a patient who has been impaled by an ice pick.