In the heart of New York City, disaster strikes when a massive explosion occurs within the Holland Tunnel. The ignition happens due to a chain reaction set off by a group of thieves escaping with toxic waste through the tunnel. The explosive force traps commuters under the Hudson River, leaving them with no clear route to safety. In response to the crisis, Kit Latura, a disgraced former EMS chief, finds himself nearby and feels compelled to act. With limited resources and time, he descends into the hazardous depths to lead a rescue mission for the survivors trapped inside the tunnel's deadly confines. As Kit confronts his past failures, he must navigate through collapsed debris, rising waters, and leaking chemicals to reach those in dire need.

The group of survivors, dealing with their own fears and interpersonal conflicts, are forced to rely on each other and Kit's decisive leadership to find a way out. Challenges mount as oxygen levels drop and structural integrity diminishes, presenting escalating dangers with every passing moment. Kit's ability to maintain hope and courage inspires the group to persist against all odds. Despite facing dwindling options, Kit uses his expertise and improvisation skills to combat various hazards they encounter. With rescuers unable to safely access the sealed tunnel, the pressure builds, necessitating swift and brave decisions. Racing against time, Kit and his companions aim to overcome perilous conditions threatening their lives at every turn.