Ernie, a young boy who hangs around the firehouse, is spotted near a garbage can fire that spread to a nearby store full of oxygen tanks. Fighting that fire, Vargas gets sent to the hospital with burned lungs and develops an infection, while Severide wants to question the boy, believing him to be an arsonist. The boy later admits that his uncle is the felony arsonist. Vargas is diagnosed with COPD, thus ending his career. He ponders jumping off the firehouse roof but Casey and Severide talk him down. Also, Severide saves a woman from a car accident and she asks him out on a date.