In the first part of a three-show, one-night crossover event, Firehouse 51 is faced with a daunting challenge when an out-of-control blaze consumes a 15-story apartment complex, trapping victims on the top floors. Complicating the rapidly escalating ... (more)situation, members soon discover that someone close to home may be one of the trapped victims. [Chicago Med S04E02 When to Let Go (2)] [Chicago P.D. S06E02 Endings (3)]