A rare but deadly bacteria takes its toll on numerous victims around the city, leaving Chicago’s finest first responders to work together alongside the CDC to resolve the dangerous situation. Following a fire at a local university that ties into the outbreak, Severide has suspicions that something bigger is happening.
Brett and Foster question the suspicious circumstances surrounding an attack at a juvenile detention center. A convoluted new technology at Firehouse 51 tests everybody's patience. Kidd is chosen to represent the district at a leadership conference.
Lt. Casey struggles to get Chief Boden to sign off on an energetic new recruit. Against her better judgment, Foster extends an olive branch to her irritating new medic. Otis inspires Herrmann to seek new partners at Molly’s. Brett realizes life in Fowlerton will take some getting used to.
The mattress factory fire spirals out of control. Truck and squad lay it on the line in hopes of getting the trapped victims out alive.