With the collapse of the towers, WTC becomes a survival film, with members of the team killed in the crash and pinning the two seriously injured survivors in a maze of jagged concrete. With no chance of freeing themselves, they can only support each other's spirits and hope they somehow will be rescued.

Cage and Peña are confined to doing most of their acting using only their faces - and with poor lighting, both still manage to shine through. Trapped about 30 feet apart, the officers talk, sometimes scream at one another in order to stay alert. Meanwhile, Stone crosscuts to their wives anxiously waiting for news. Allison Jimeno (Maggie Gyllenhaal), pregnant with the couple's second child, comforts their 4-year-old in New Jersey as their extended family prays. Fifty miles away in southern New York, Donna McLoughlin (Maria Bello) and their children nervously follow the grim news reports while well-wishers offer hollow-sounding encouragement.

The movie profiles those who plunged into the flaming debris to help find trapped officers; Emergency Service Unit officer Scott Strauss (Stephen Dorff), paramedic Chuck Sereika (Frank Whaley) and Dave Karnes (Michael Shannon), an accountant who bravely marched to ground zero to do what he could.