On New Year's Eve, a mysterious killer shot and killed a large number of revelers in a high-rise building in the center of the United States. 29 people died, and no evidence such as bullet shells and fingerprints were found at the scene of the crime, and there was no trace of the killer. Three days later, the killer went on a killing spree in a large shopping mall again, and dozens of citizens and security personnel were shot and killed. A group of SWAT team members were also killed by the killer with grenades. FBI Director Lanmark (Ben Mendelsohn) and his beloved apprentice, the young policewoman Eleanor (Shailene Woodley), were ordered to investigate the case, but the state government and the local police department tried to seize the credit, fight for power, and even carried out SWAT operations that Lanmark strongly opposed, but the casualties caused by these operations were attributed to Lanmark, which was ridiculous and completely out of control. It is this absurd evil world that shaped today's killers. When the master and apprentice were at a dead end, Eleanor found a key clue that brought her infinitely close to the abyss of the evil world.