A deaf girl gets mixed up in drugs and free love while searching for her missing brother.

Jennie Davis, a 17-year-old deaf runaway, arrives in San Francisco's Haight-Ashbury district to search for her missing brother Steve, an artist. Wandering into a hippie coffee shop, she meets Stoney, Ben, and Elwood--three members of an unsuccessful rock group. They help her elude two policemen who are looking for her and persuade her to exchange her "square" clothing for something more suitable. With the help of Stoney's friend Dave, they continue to search for Steve but find no trace of him. After learning that some young thugs are also looking for Steve, Stoney runs into Steve and talks him into visiting Jennie at the hangout where Stoney's combo is performing. Though Steve appears there the next day, he is forced to flee when he is spotted by the thugs. Dave takes the near-hysterical Jennie to Stoney's apartment, where he attempts to quiet her down and then seduce her by giving her a psychedelic drug. Unaware of what she has swallowed, Jennie runs out in the night to continue her search for her brother, who, unable to escape from his pursuers, has barricaded himself in his house and set fire to it. Jennie arrives in the area and wanders into the traffic on the Golden Gate Bridge. Stoney and Dave come to her rescue; but Dave, also in a daze, is killed by a car while carrying Jennie to safety. United by their mutual contempt for the outside world, Jennie and Stoney leave together.