: Firehouse 51 responds to a major fire at Central Chicago University . While inside, Kelly Severide notices a laboratory wall bearing the same "BRT" initials the original victim mentioned.
As the medical crisis unfolds, the teams begin to suspect this isn't a natural occurrence.
: Shortly after, Ambulance 61 discovers two more victims dead from the same infection in a private residence.
The story begins with a rare and terrifying (necrotizing fasciitis) that begins spreading rapidly across the city. The Outbreak Begins