When a commuter ship capsizes, the ED finds itself under water as the staff struggles to treat the influx of new patients and deal with bold new employees taking charge.

Lenox continues to rankle Archer as the two tackle their new roles; Ripley faces possible suspension over what really happened to Pawel; Goodwin is forced to make layoffs.

Hannah treats a woman whose undiagnosed condition threatens the lives of both her and her unborn child. Goodwin receives a chilling message while battling the hospital higher-ups.

A familiar face returns to the ED. Ripley and Charles treat a woman with a rare disorder. Frost suspects that his patient's father is lying about his daughter's condition.

Halloween chaos takes over the ED. Asher helps a pregnant woman with an autistic son. Charles clashes with Nurse Jackie on a psych case.

Chicago P.D. steps up Goodwin's security after she's threatened online by a former employee. Archer and Frost treat victims from a disciplinary camp injured during a rockslide. Maggie gets roped into delivering a high schooler's baby.

Ripley and Frost uncover shocking information that conflicts with their patient's DNR. Asher facilitates an unexpected reunion. The tension between Archer and Lenox comes to a head.

Goodwin's troubles persist. Charles clashes with his former resident over a depressed patient. Lenox and Ripley treat a car accident victim who recently reunited with his college sweetheart.