Sylvie witnesses a murder and is threatened by the shooter not to go to the police. Firehouse 51 jumps into action when a fire breaks out at a restaurant and traps several people inside a vault. Mouch starts to get cold feet.

Amy Morton, Elias Koteas, Erin Allegretti, Jon Seda, Lauran September, Marina Squerciati, Miranda Rae Mayo, Robyn Coffin