In October 1975, George Manning, Seymour Cassel, a successful San Francisco Bay Area businessman, is left home alone on his 40th birthday while his wife Karen Manning Beth Brickell tends to a family emergency. A thunderstorm rages that evening as two attractive young women, Agatha Jackson Sondra Locke and Donna Colleen Camp, explain that their car broke down and they need a place to dry off and make a quick call for a ride. He invites them inside, and the air of casual hospitality gives way to a tense intimacy as Jackson uses the bathroom sauna, Donna soon joins her, and George, driven by a mix of curiosity and loneliness, walks in on them bathing in the hot tub. The happily married man is drawn into a seduction that quickly becomes coercive, and the night tilts from convivial to perilous.
The next morning, George wakes to find the two women cooking breakfast and still present in his home, with evasive explanations about why they never left. It becomes clear that they have no intention of departing; they begin rummaging through the house’s contents, trying on his wife’s clothes, and even vandalizing the property. George, increasingly unsettled, threatens to call the police, but Jackson claims that the pair are underage and warns of the severe consequences he would face if discovered. A visiting maid nearly uncovers the ruse, and the tension sharpens as George tries once more to contact authorities—only to be met with lingering deceit from his unwelcome guests. Eventually Jackson agrees that they will leave, but only if George drives them somewhere.
Reluctantly, George ferries them to a city bus stop across the Golden Gate Bridge, hoping the nightmare is over. Yet when he returns home that night, the pair ambush him inside the house, subdue him with bedsheets, and escalate their assault while continuing to trash the place and paint his wife’s makeup across their faces. Their sadistic game expands to include a brutal act against a grocery delivery man, whom they drag into the living room, bludgeon, and drown in a fish tank. George’s few attempts to resist are quashed, and the captors’ control deepens as they reveal that their actions are rooted in a tangle of trauma and warped power.
During the long night, Jackson exposes a painful backstory: her father’s sexual abuse has left her life in fragments and fuels her erratic behavior. The two enact a mock trial among themselves to determine whether George should be punished for alleged sexual crimes he “committed” the previous evening. At midnight, Jackson, acting as both witness and judge, declares him guilty and sentences him to death at dawn. By six o’clock, Donna holds him down while Jackson readies a large cleaver, preparing to execute him. In a stark reversal, she spares his life at the last moment, and the two depart, laughing maniacally as they stroll through the neighborhood.
Their triumphant escape turns abruptly comic tragedy as they stroll into the street and—unaware of their surroundings—are struck head-on by a speeding van, ending the ordeal they had imposed on George and leaving the outcome uncertain for the man they tried to break.
