Watch The January Man Online

On New Year's Eve, 1988, a wealthy Manhattan socialite named Alison Hawkins returns home from the evening's festivities. As she feeds her fish before going to bed, she is strangled to death by an undetected intruder with a blue ribbon. It is the latest murder by a serial killer known as The January Man, who has been terrorizing New York for eleven months. New York City Mayor Flynn is frustrated up with the lack of progress in tracking down the killer, and tells NYPD commissioner Frank Starkey to "get brother, and get him now." Flynn and Frank know that Nick is the only man brilliant enough to catch this killer. This is a controversial assignment for Frank, as two years ago, Nick was disgraced in a graft scandal, and expelled from the force, by Frank. Frank goes to the scene of a raging fire to find Nick, who had been become a firefighter. Nick makes a memorable entrance, bursting through a window with a child in tow, escaping the fire. Frank talks Nick into returning, but only on the condition that he be able to cook dinner the next night for Frank's wife, Christine, who is Nick's ex-girlfriend. After a press conference announcing Nick's reinstatement, Christine and Nick shared a dinner. Old wounds are opened up, and evidence is hinted at that Frank was involved in the scandal that got Nick fired in the form of a cancelled check.

Police Captain Alcoa is not happy with Nick's return, having despised his beatnik attitude but respected his abilities as a detective, but has to go along with the mayor's demand that he supply Nick with anything needed to solve the case. After reporting for work, Nick shows his eccentric side by taking a different office than the one he was assigned because the light was not to the liking of his painter friend, Ed, to work with. After getting Alcoa to add the equally-eccentric Ed to the payroll as his assistant, Nick begins to work on the case. His first lead is to speak to the mayor's daughter, Bernadette, who was a friend of Alison Hawkins, and the last victim, but during their first meeting, they end up having sex. After Nick has Bernadette take him to Alison's apartment, Nick decides to let Bernadette stay at his apartment, because she is too frightened to return to her own, which she fears is publicly known. Christine eventually tells Mayor Flynn of this relationship.

Nick discovers that all of the eleven previous murders occurred on dates that are prime numbers, all of which are among the twelve prime numbers possible up to the number 31. Because the only one of the twelve prime numbers that has not been used is 5, he knows that the next murder will take place the next night, the fifth of the month. Nick is apparently proven wrong on when the killer will strike next when the January Man apparently strangles another victim one day ahead of Nick's prediction, then leaps out the window to his death. Nick believes that this is a copycat killing, especially when he learns that the man broke a window, as opposed to picking a lock to gain entrance as in the other murders, but to the political and media-minded Frank and Flynn, it is a closed case. Nick loses credibility in the eyes of Flynn, Frank, and Alcoa.

Nick convinces Alcoa to provide backup so can set a trap, and in exchange, Nick will transfer back to the fire department as soon as the day is up. Nick and Ed figure out that the position of the buildings the victims were murdered in, when seen on a map of Manhattan, forms the shape of the constellation Virgo. They also realize that the all the rooms in which the murders took placed have windows facing out the front of the building, and that when the exterior positions of the windows are lined up together according to which floor they are on, they correlate to 11 notes of the song "Calendar Girl". With the help of the computer's "Music Maker" program, figure out the building and floor of the killer's next strike. Ed finds out that there are two women who live in apartments that have a window that faces the front, and one of them has gone to Disney World.

Nick sets a trap with Bernadette as bait, outfitting her with a neck guard to prevent the January Man from killing her. The trio stake out the room in a supply closet and witness the January Man picking a lock to get into the apartment. The trio intercept the apartment's resident and send Bernadette in, where she is attacked. Nick breaks in and and after a prolonged struggle with the killer, manages to subdue him. Christine gives Nick the cancelled check, eliminating any doubt that Frank was behind the scandal. She tells him that she left Frank, and wants to renew their relationship, but Nick is not interested, and invites Bernadette to dinner.