Maureen Coyle was a novitiate to become a Catholic nun. As she grew closer to taking her final vows she began to question her relationship to God and religion in general. This was triggered mostly by sexual feelings she was having trouble denying herself. She intended to kill herself by throwing herself from the tower at her convent but she was saved by Sister Margaret.
Coyle left the convent in shame and while hitchhiking was picked up by Duane Duke. When Duke tried to force a sexual encounter, Coyle left his vehicle. The next day she stumbled upon Statler's Cafe where she was pointed to the Bates Motel as an inexpensive place to stay. At the motel, she encountered Duke again and he apologized for his behavior while offering her a room at the motel. She accepted the gesture and paid the price. Coyle once again tried to kill herself. This time, she slit her wrists in the bathtub.
Meanwhile, Norman Bates had seen the initials M.C. on Coyle's suitcase. This reminded him of Marion Crane and the two parts of his mind began arguing about Coyle being a bad influence on Norman. Norman dressed as his Mother and headed to Coyle's cabin to kill her. When he found her dying in the bathtub he saved her life. Coyle was taken to St. Matthew's Hospital where she was treated by a psychiatrist called Father Brian. Norman asked her to stay at the motel until she heals.
Later that week, Norman and Maureen went on a date. Norman had such strong feelings for her that he feared for her safety from his Mother side. He refused to have a physical relationship with her.
A reporter from Los Angeles, named Tracy Venable informed Maureen of Norman's past. Maureen believed she was sent by the Virgin Mary to help Norman. When Maureen visited Norman in the Bates House he was distracted by the voice of his Mother and pushed Maureen down the stairs. At the bottom, her head was impaled by a sculpture of Cupid with an arrow. She was killed.
In a deleted scene that was posted on Youtube, Norman (dressed as mother) purposely kills Maureen by whacking her with his knife, sending her down the stairs and hitting the arrow of the statue, Norman follows as Maureen drops to the ground and has one last look at Norman, who finishes her off by stabbing her with his knife off-screen, Echoing Milton Arbogast's death from the first movie.