Synopsis

A lingering threat hangs over the firehouse following a previous call, leaving a dangerous individual with a personal score to settle against Lieutenant Casey and Firehouse 51, prompting the involvement of the CPD. Dennis Mack, a firefighter and close friend of Severide’s father, arrives in town to observe the squad, though his presence may conceal hidden agendas. Simultaneously, Brett and Antonio navigate complications in their relationship as Antonio’s ex-wife, Laura, unexpectedly reappears, a