Plot
Forty-something New York psychologist Dr. Bill Capa falls into a deep depression after his unstable patient Michelle commits suicide before his eyes by jumping from his office window. The sight of the body clad in a bright green dress lying in a pool of blood causes him to suffer from psychosomatic color blindness, taking away his ability to see the color red. Bill travels to Los Angeles to stay with a friend, fellow therapist and former college colleague Dr. Bob Moore, who invites him to sit in on a group therapy session.
The therapy group includes: Clark, a temperamental attorney with OCD; Sondra, a nymphomaniac and kleptomaniac; Buck, a suicidal former police officer; Casey, who paints sado-masochistic images; and Richie, a 16-year old with gender dysphoria and a history of drug use. As Bill spends the next morning with Bob, the latter confides that his house is heavily protected due to anonymous threats, which he believes are connected to the group. He had contacted the police, but as therapists are often threatened they are not taken seriously.
However, soon after Bob is violently murdered in the office, Bill is plunged into the mystery of his friend's death. Lt. Hector Martinez considers everyone in Bob's therapy group, including Bill, as suspects in the murder. Bill continues to live in Bob's house and begins an affair with Rose, a beautiful but mysterious young woman he meets after she rearends his car one day, who comes and goes. Bill takes over the therapy group, initially upon Martinez's suggestion as a way of assessing the possible suspects.
Dale Dexter comes to the psychology office, trying to convince Bill to release his brother Richie from the group sessions. As social services took over, he is a ward of the state. Dale insists he would be better off without. When Bill looks into the Dexters, they had been thrown into the system four years ago when Richie was 12 and put under the psychological care of Dr. Niedelmeyer, but disappeared from their radar until recently.
Bill visits Sondra, so her friend Bonnie ducks out. When he asks her about Richie, she mentions he was molested years ago. Bill asks, due to an isolated attack by him, if Sondra thinks the teen is prone to violence. She whole-heartedly declares Richie could never hurt anyone, naming Clark as a more likely suspect.
Clark gets a home visit from Bill. Clark confesses he has slept with Sondra, hence their mutual animosity. Clark's OCD does not allow him to see her much. He mentions he is seeing a small, tidy woman.
Rose spends most of a day with Bill at Bob's. They look through an old album of photos, where there are several photos of the college friends, with early photos with their wives at the time. Rose asks to see more recent ones of Bill. He produces one he had found hidden, but she quickly changes her mind after seeing a few. As Bill goes to shower, Rose slips photos out, which he catches so she runs out.
After Casey is murdered, Bill becomes the target of several attempts on his life. He discovers that all but one of his patients have been romantically involved with "Bonnie". He eventually learns that both "Bonnie" and "Richie" are really Rose, and the murders were the work of her deranged brother, Dale. They once had an actual brother named Richie, who hanged himself after being molested by his child psychiatrist Dr. Niedelmeyer, who also abused Dale.
After Richie committed suicide, Dale abused Rose into playing the part of their brother. Rose began to re-emerge during therapy and, under another personality named "Bonnie", started relationships with the other patients. Dale proceeded to kill them, fearing that they would soon link Rose to Richie.
Dale kidnaps Rose, and tries to kill Lt. Martinez and Bill with a nail gun when they arrive to rescue her. At the last moment, Rose frees herself and kills Dale with his nail gun, as he is distracted answering Bill's questions. Deeply traumatized, she immediately tries to commit suicide, but Bill chases after her and convinces her to keep living. As they kiss, he regains the ability to see the color red.
