Chicago P.D. steps up Goodwin's security after she's threatened online. Archer and Frost treat victims from a disciplinary camp injured during a rockslide. Maggie must deliver a teenager's baby.

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

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.

Asher 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.

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.

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.