The Stepfather

A man washes off blood in a bathroom, changes his appearance, puts his belongings into a suitcase, and leaves through the front door of his house, nonchalantly passing the butchered remains of his family. Boarding a ferry, he throws the suitcase containing the items from his former life overboard. One year later, that man — now a real estate agent using the name Jerry Blake — has married a young widow named Susan Maine and is living in a suburb of Seattle. Jerry's relationship with Susan's 16-year-old daughter Stephanie is strained. She is suspicious of Jerry's intentions, but Susan and Stephanie's psychiatrist, Dr. Bondurant, urge her to give Jerry a chance. Meanwhile, Jim Ogilvie, the brother of Jerry's murdered wife, runs an article about his sister's death in the newspaper and attempts to find the man who killed her, who used the name Henry Morrison. While hosting a neighborhood barbecue, Jerry discovers the article and is disturbed by it. He goes into the basement and begins shouting maniacally, unaware that Stephanie is also in the room. Discovering his stepdaughter, Jerry claims he was simply letting off steam and tells her not to worry. Stephanie finds the article about the earlier killings and decides her stepfather might be the murderer. She writes to the newspaper requesting a photo of Henry Morrison, but Jerry intercepts it in the mail and replaces it with a stranger's photo, allaying her suspicions. Curious about Stephanie's stepfather, who has refused to meet him, Dr. Bondurant makes an appointment with Jerry under an assumed name, saying he wants to buy a house. During their meeting, Bondurant asks too many personal questions and Jerry realizes that Bondurant is not who he says he is. Believing Bondurant is investigating him, Jerry beats him to death with a plank, puts him in Bondurant's car, and sets the car on fire. Jerry later informs Stephanie of Bondurant's death, claiming he was in a car accident, and succeeds in bonding with her. However, Jerry's newfound relationship with his stepdaughter is cut short when he catches her kissing her boyfriend Paul. Jerry angrily accuses Paul of attempting to rape Stephanie, driving Paul away. Stephanie also runs off when Susan says Jerry is her father, which she angrily denies, causing Susan to slap her. That incident also drives Jerry to anger. The next day, Jerry quits his job and starts creating a new identity for himself in another town. He begins courting another single mother while planning to murder Susan and Stephanie. Having figured out the town where Jerry could be living, Jim begins going door to door in search of his former brother-in-law. After Jim stops by, Susan phones the real estate agency to tell Jerry that someone was looking for him, only to be informed that Jerry quit several days ago. Susan asks Jerry about this, but while explaining himself to Susan, he confuses his identities. Realizing his mistake, Jerry bashes Susan on the head with the phone and pushes her down the basement stairs. Assuming Susan is dead, Jerry sets out to kill Stephanie. Jim, who has realized that Jerry is the man who killed his sister's family, arrives wielding a revolver, but Jerry stabs him to death before Jim can shoot him. After terrorizing Stephanie, Jerry corners her in the attic, only to fall through the weak floor into the bathroom. Before he can kill Stephanie, Susan appears and shoots Jerry twice, but he is still able to reach his knife. Stephanie wrests it away and stabs him in the chest. He weakly utters "I love you" before tumbling down the stairs. Stephanie later cuts down a birdhouse that she and Susan had helped Jerry install.