A group of schoolgirls and their teachers are traveling through the rural English countryside when their bus breaks down near an isolated village. Seeking shelter, they find a seemingly abandoned mansion to spend the night. Unbeknownst to them, four escaped mental patients, who have been experimented on with LSD, have also taken refuge in the same vicinity. The patients believe they are in a dream state where their actions have no real consequences. This delusion leads to a series of violent and terrifying encounters as the girls and their teachers attempt to survive the night in increasingly dire circumstances.

Meanwhile, the local authorities and a couple of bystanders become aware of the catastrophic events unfolding in the mansion. The tension mounts as outsiders try to reach the isolated location to offer help, but time is running out. As the night deepens, paranoia, fear, and madness escalate, turning their struggle for survival into a frantic race against time. The relentless pursuit by the deranged men drives the group to desperate measures, culminating in a battle where only their wits and willpower stand between them and unimaginable horror.