Psycho II is a 1983 American slasher film directed by Richard Franklin, written by Tom Holland, and starring Anthony Perkins, Vera Miles, Robert Loggia, and Meg Tilly. It is the first sequel to Alfred Hitchcock's 1960 film Psycho and the second film in the Psycho franchise. Set 23 years after the first film, it follows Norman Bates after he is released from the mental institution and returns to the house and Bates Motel to continue a normal life. However, his troubled past continues to haunt him as someone begins to murder the people around him. The film is unrelated to the 1982 novel Psycho II by Robert Bloch, which he wrote as a sequel to his original 1959 novel Psycho.
In preparing the film, Universal hired Holland to write an entirely different screenplay, while Australian director Franklin, a student of Hitchcock's, was hired to direct. The film marked Franklin's American feature film debut.
Psycho II was released on June 3, 1983, and grossed $34.7 million at the box office on a budget of $5 million. It received mixed-to-positive reviews from film critics. The film was followed by Psycho III (1986).
Aljean Harmetz of The New York Times wrote that a sequel being made 22 years after the original was "unusual".
Twenty-two years after his killing spree, Norman Bates has overcome his delusions and accepted that his mother is dead. Having never been convicted of murder—he was found not guilty by virtue of his insanity—Bates is released from a mental institution by the court, after being deemed mentally sound. Marion Crane's sister Lila, the widow of Marion's former lover Sam Loomis, vehemently protests Norman's release, but her plea is dismissed. Against the advice of Dr. Bill Raymond, Norman takes up residence in his old home behind the Bates Motel. He reports to a prearranged job at a nearby diner, where a woman named Emma Spool works. After work, a young waitress at the diner, Mary Samuels, has been thrown out of her boyfriend's place. Norman offers to let her stay at the motel, then extends the offer to his home when he discovers that the motel's new manager, Warren Toomey, has been using the motel to deal drugs. He immediately fires Toomey.
Norman's assimilation into society appears to be going well until he begins to receive mysterious phone calls and notes from "Mother" at the house and diner. During a work shift, a drunk Toomey picks a fight with Norman, who suspects him of leaving the messages. Shortly after, a figure in a black dress stabs Toomey to death as he is packing to leave the motel. Becoming increasingly sympathetic to and impressed by Norman's fight to keep his sanity, Mary takes up permanent residence in a guest room at his house.
While Norman is renovating the motel, he hears voices in the house, and enters his mother's bedroom to find it exactly as it was 22 years ago. A sound lures him to the attic, where he is locked in. Meanwhile, a teenage couple sneaks in through the cellar window to have sex. They notice a female figure pacing in the next room. As they try to climb out, the boy is stabbed to death. The girl escapes and alerts police. Mary finds Norman in the attic and he shows her his mother's bedroom, only to find it back to its state of disuse. The sheriff arrives and questions them about the boy's murder. Mary claims they were out walking together at the time. After the sheriff leaves, Norman rebukes her for lying. He fears he may have killed the boy, since Mary told him the attic was unlocked when she found him.
That evening, Mary and Norman find a bloody rag stuffed in the toilet. Norman is horrified, believing he has committed another murder, but Mary insists he is innocent. Mary goes down to check the motel. In the parlor she is surprised by Lila, her mother; Lila and Mary have in fact been making the phone calls and notes, even posing at the window dressed as Norman's mother. Mary altered his mother's bedroom and locked Norman in the attic so she could change it back. All of this was an attempt to drive Norman insane again and have him recommitted. However, Mary's growing friendship with Norman has convinced her he is no longer capable of killing. She suspects someone else is in the house, pointing out that Norman was locked in the attic at the time of the boy's death.
Later, Norman becomes too terrified to leave his room, saying he saw his real mother in the house. Mary admits to Norman that his sanity is beginning to erode and stays to comfort him.
Dr. Raymond discovers Mary's identity as Lila's daughter and tells Norman that the two of them must be the ones harassing him. He also has the corpse of Norman's mother exhumed, to prove Norman is not being haunted by his mother. Norman is only partially convinced, saying the one behind everything must be his "real mother", despite there being no record of him being adopted. Norman confronts Mary with what Dr. Raymond told him. She says that she has given up her part in Lila's ruse, but Lila will not stop.
While Lila is retrieving her "Mother" costume from the cellar, a figure steps out of the shadows and murders her. Meanwhile, the police dredge the swamp and find a car with Toomey's body in the trunk. Mary runs to the house to try to convince Norman to flee. Norman answers the phone and starts speaking to "Mother". Mary listens in; nobody is on the line with Norman. While Norman debates with "Mother" about her command to kill Mary, she runs into the cellar and dresses up as Mother, complete with butcher knife, in an unsuccessful bid to get Norman to "hang up". Dr. Raymond foolishly grabs her from behind, thinking he has caught her in the act of trying to drive Norman insane, and in her fright Mary accidently turns and plunges the butcher knife into his heart.
Confronted by the sight of "Mother" standing over Dr. Raymond's bloody corpse, Norman's sanity finally snaps and he advances upon Mary, babbling. Mary backs into the fruit cellar and tries to protect herself from the advancing Norman. She stumbles upon Lila's body, buried in a pile of coal. Assuming Norman is responsible, Mary raises her knife to kill him but is shot dead by the incoming police. The ensuing investigation is inconclusive, but in light of an overheard argument between Mary and Lila, Mary's attempt to kill Norman, and her dressing as his mother, the police incorrectly determine Mary most likely committed all the murders.
Later, Emma visits Norman and informs him that she is his real mother, and that Mrs. Bates was her sister, who adopted Norman as an infant while Emma was institutionalized. She reveals that she was the real murderer, having killed anybody who tried to harm her son. In response, Norman strikes her in the head with a shovel, killing her. He then carries the body upstairs to Mother's room, and begins talking to himself in her voice, signifying that Norman's “Mother” personality has once again taken control of his mind.