A member of Firehouse 51 clings to life and takes a sudden turn for the worse as medical staffers race to give treatment. Meanwhile, Dr. Natalie Manning prepares for her pregnancy and members of Chicago P.D. probe the case of a woman pulled from a fire.

The crossover starts on Chicago Fire S04E10 The Beating Heart (I). It continues on Chicago P.D. S03E10 Now I'm God (III).

Dr. Halstead jeopardizes his career when he goes against a family's order regarding a terminally ill cancer patient. Meanwhile, April and Dr. Reese treat a homeless man, and Choi's personal issues emerge while caring for a bipolar patient.