While rigging explosives to raze an eight-story building, members of a 21-man demolition team are trapped inside when one of the volatile nitroglycerin blasting caps accidentally detonates, causing several floors of concrete slabs to collapse. Responding to the emergency call, police officers Yokas, Bosco, Sully and Davis control the crowd of spectators. Paramedics Kim, Bobby, Doc and Carlos, along with Doherty and other firefighters, enter the building to find the missing workers. As Doherty radios that gas is leaking and at least three support columns are off their piers, another explosion occurs.
Eventually, only two workers remain missing and trapped. With the steel beams of the structure groaning from metal fatigue, the Chief orders all personnel to vacate the unstable edifice. Bobby and Kim hear the plaintive calls of the two men, Frank Hagedorn and his young brother-in-law, Jack , both pinned under a four-ton slab of concrete. When it becomes clear that Jack will be crushed after the slab is lifted, he asks to make a video recording for the daughter he has never communicated with. Bosco and Yokas make a deal with an aggressive TV news reporter to use her camera in return for exclusive rights to air the tape. As Doherty begins inflating air bags to raise the concrete, the weight shifts, and now it is Frank--not Jack--who will die. Frank's wife and child view his emotional farewell on videotape.
Meanwhile, Fred Yokas' drinking escalates. Doc cancels his date with Brenda because he says she looks like his dead wife, but Carlos sees no resemblance. Davis seeks reassurance from Sully that the veteran officer will not date Davis' mother, Maggie.