Will Dormer (Al Pacino) and his partner Hap Eckhart (Martin Donovan) came to Alaska, a small town far from Los Angeles where the sun never sets, to investigate a case in which a 17-year-old girl was beaten to death. A female police officer in Alaska, Llie Burr (Hilary Swank), was sincerely in awe of Dormer's handling of the case and tried to learn in the process of investigating the case. At this moment, Dormer was actually in trouble. He captured a suspect in Los Angeles. In order to convict him, he had to fabricate false evidence, and the matter was investigated by the Ministry of Internal Affairs. Hap wanted to tell the truth to the Ministry of Internal Affairs and thought it was a good thing for Dormer, but Dormer didn't think so. In the roundup to lure the real murderer, Dormer accidentally killed Hap in the fog. Before Hap died, he thought Dormer had deliberately killed himself. When stating the incident, Dormer instinctively said that the gun was fired by the murderer. However, under the pressure of conscience and the sun never sets, he suffers from severe insomnia. At this time, people start calling him, claiming to have seen everything in the fog. Dormer finally locks the murderer on the detective novelist Walter Finch (Robin Williams), who does not intend to play hide-and-seek with him. A psychological and conscience duel begins.