- Steven Weber (Dr. Dean Archer)
- Jessy Schram (Dr. Hannah Asher)
- Luke Mitchell (Dr. Mitchell 'Mitch' Ripley)
- Sarah Ramos (Dr. Caitlin Lenox)
- Darren Barnet (Dr. John Frost)
- S. Epatha Merkerson (Sharon Goodwin)
- Oliver Platt (Dr. Daniel Charles)
Episode: Malignant (II)
Air Date: 2016-01-05
Runtime: 44 min
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).