Johnny (Anthony Michael Hall), now fully recovered from his recent coma, heads to the bus station to pick up Sarah's college friend Elaine (Maxim Roy). Shortly after her arrival, Elaine questions him about the status of his relationship with Sarah, specifically asking him why he's not moving faster. But before he can respond, a vision catapults him into a scene of absolute mayhem. In this horrifying vision, a massive fireball consumes the entire bus station, engulfing masses of terrified people. Johnny comes back to reality reeling from the explosion. He has 51 minutes to save dozens of lives, including his own! Elaine, who creates crossword puzzles for a living, jumps on the case, using her puzzle-solving expertise to put the explosion into perspective. She suggests treating the potential disaster like a puzzle, and tracing the clues backwards to get to the source of the riddle. Every puzzle, however, takes time to solve and time is the one thing Johnny doesn't have.

The race begins and Johnny has to beat the clock to reveal the source of the explosion. Searching for the trigger, he bounces from a disabled and depressed war veteran, to a dejected divorcé, to a lonely maintenance worker. Every time Johnny thinks he's averted the explosion by altering events, he's hit with another vision that proves otherwise. As the minutes tick by, he's dogged by Homeland Security and the daunting challenge of singling out his suspects in a sea of people. Just before time runs out, Johnny realizes that sometimes the final solution to the most difficult of puzzles is the one you least expect.