David Goodloe

Halstead returns to Med to help Goodwin with a secret investigation; Archer and Charles deal with twins who insist on being identical inside and out; Stevie and Dylan treat a young patient with sickle cell anaemia.

Severide struggles with the cost of helping Det. Pryma with the Martucci case; Gallo campaigns for Herrmann to represent 51 at the National Firefighter's Association's Winter Conference; a familiar face makes a shocking return.