At first, stopping off at the abandoned mental hospital seems like a fun idea for a bunch of teenagers en route to a summer youth camp. But when the van breaks down in the heat of the day, leaving them stranded, the polite and friendly veneer peesl off the group and they discover they don't get along as well as they'd thought.
Then one by one, they start disappearing.
The teenagers have been unwittingly drawn into the dark past of the adolescent psychiatric unit, as experienced by Gideon, a former resident who hasn't lived there since the 1970s.
A mental patient with a long history of violence, Gideon is acutely unwell. After attacking his support worker and fleeing his council flat, he has returned to his bed in the rambling, maze-like hospital which shaped his mind.
Rather than being a safe place, a refuge, an asylum, Lake Malice was Gideon's personal hell. Now dwelling alone among the empty, overgrown and decaying buildings, he relives the past trauma of institutional abuse, and persecution he suffered at the hands of his fellow adolescent patients. Gideon is hardly surprised when one sunny day he finds his tormentors have returned. But this time, they are weak and he is strong.
As the sun sets, the youth group find they are being called into account for the sins teenagers past, and pursued by a furious, remorseless, insane killer who comes after them with the full force of forty years of resentment.
Will any of them escape? Or will the Lake Malice adolescent unit finally have all its beds full again?