In Upstate New York, a waste management company embarks on an illegal operation, loading toxic waste barrels onto trucks to dispose of them secretly. Having bribed a guard, they plan to pass through a crucial highway tunnel that connects Manhattan to New Jersey, on a fateful night between 11 PM and midnight. Among the unsuspecting motorists in the tunnel are Maddy Thompson (Amy Brenneman), a struggling playwright who is trying to escape her recent misfortunes, including yet another rejection of her play and heartaches related to her personal life. She is joined by a bus filled with juvenile offenders, including Mikey (Renoly Santiago), Kadeem, Vincent, and Laytona; a family of vacationers led by Steve Crighton (Jay O. Sanders), his wife Sarah (Karen Young), and their teenage daughter Ashley; as well as an elderly couple and their dog, led by Roger Trilling (Colin Fox) and Eleanor (Claire Bloom), who are traveling with their son’s dog Cooper. Among the commuters is also the athlete Roy Nord (Viggo Mortensen).
Inside the tunnel, George Tyrell ([Stan Shaw]) works as a transit cop, while his girlfriend Grace (Vanessa Bell Calloway) manages tunnel operations. The structure, built deep under a riverbed in 1921, becomes the scene of chaos when a group of diamond thieves, in an attempt to escape law enforcement, crash into a truck filled with the toxic waste. The collision triggers a catastrophic explosion that devastates the tunnel, leading to a disastrous fireball that engulfs most of the vehicles inside, effectively sealing off the tunnel from both ends.
At the threshold of the tunnel, Kit Latura (Sylvester Stallone), a former New York City Emergency Medical Services Chief, now a taxi driver, witnesses the fiery eruption and springs into action. He encounters an old colleague who warns him of the dire situation—the tunnel is at risk of total collapse. Meanwhile, Chief Dennis Wilson attempts to coordinate a response from the other side of the tunnel, dismissing Kit's bold suggestion to use explosives for rescue efforts.
Amidst the chaos, Maddy takes it upon herself to rescue the trapped juvenile offenders from a prison bus. As the situation intensifies, Kit must navigate the treacherous environment, racing against time and the rising water levels that threaten the lives of those trapped. The air in the tunnel is limited, and the survivors rally around each other in hopes of finding an escape.
Kit's resolve is tested as he ventures deeper into the tunnel, risking his safety through the ventilation system while attempting to direct the survivors toward a platform with better prospects for escape. Unfortunately, tragedy strikes when Nord, who took the lead in seeking a potential exit, abruptly meets his demise in a sudden collapse.
As water begins seeping in from the river above, Kit's determination remains unyielding. He devises a risky plan involving explosives to alleviate the water flow and manages to aid in the rescue of fellow survivors, including George Tyrell, who faces grave injury but is saved just in time. Time is against them as more people confront Kit, desperate and anxious for a way out.
In a poignant moment, Eleanor succumbs to the harsh conditions, leaving her husband to grapple with their loss. Kit makes yet another daring decision, descending into perilous waters to retrieve Cooper, the lost dog, just as the structure begins crumbling further.
As the story unfolds, the heroes make desperate attempts to find a way out of their dire circumstances, leading to a heart-stopping climax involving explosives and a frantic struggle for survival. As they find themselves closer to freedom, Kit and Maddy endure the turmoil, showcasing the depths of human resilience and the bonds forged in adversity. In a heartwarming conclusion, amidst the chaotic aftermath, they emerge to daylight, leaving behind a harrowing chapter, while Maddy insists on staying with Kit, setting the stage for their future ahead.
