That Cold Day in the Park is a 1969 psychological drama thriller film directed by Robert Altman and starring Sandy Dennis. Based on the novel of the same name by Richard Miles and adapted for the screen by Gillian Freeman, it was filmed on location in Vancouver, British Columbia, where the events occur. The supporting cast includes Michael Burns, Luana Anders, John Garfield Jr., and Michael Murphy.

Plot

Frances Austen, a woman who has inherited her late parents' Vancouver apartment, notices a nineteen-year-old boy sitting in the rain in a nearby park and invites him inside. The boy does not speak but appears to understand everything. Frances runs a bath for him, gives him a meal, and makes up a bed in her spare room; when the boy has settled down for the night, she quietly locks him in. Frances buys him new clothes the next day. That night the boy slips away through the spare room window. He briefly visits his parents and younger siblings, then goes to a houseboat owned by his older sister, Nina. He tells Nina and her boyfriend Nick what has happened to him. He is perfectly well able to speak, but Nina explains to Nick that he has a habit of going mute and refusing to talk to people. The three of them share cookies, home made by Nina and containing cannabis.