As dismembered legs begin appearing across Istanbul, Commissioner Fatih and his partner Doruk—a U.S.-trained forensic psychiatrist—race to catch the killer, even as Doruk’s wife Beyza, haunted by mysterious blackouts, discovers a chilling connection between her missing time and the victims.

"Not knowing" focuses on the life of a family that is not satisfied with their lives. Selma and Sinan are a couple who now find it difficult to endure each other. Umut, the son of the house, is after to prove himself. At the end of high school, rumors start circulating about Umut, who is homosexual. While Selma and Sinan are trying to cope with their tiring marriage, Umut suddenly disappears when the rumors go away and his head disappears. While Selma and Sinan are looking for their son, he realizes that they have actually lost themselves.