A cargo ship accidentally explodes, and agent Doug (Denzel Washington) is ordered to investigate. However, when he arrived at the scene, he found that it was clearly his first time in this place, but he was very familiar with the scene in front of him. After careful investigation, Doug discovered that the explosion was closely related to him. He used the government's Time Laboratory, where he could learn about anything happening anywhere in four days, and discovered that he had an unusual relationship with a mysterious woman who would cause a future disaster involving him! Doug must go back in time and direct history from one reality to another to prevent this disaster.