A gang of thieves gather at a safe house following a robbery, but a detective is on their trail.
When a motorbike gang kills an occultist, the evil spirit he was summoning inhabits a damaged bike. The bike is then bought and restored, but reveals its true nature when it tries to exact vengance on the gang, and anyone else who gets in its way.
When Matt Denant (Gerald de Maurier) finds himself wrongly imprisoned for manslaughter, he takes an opportunity to escape from jail during a foggy day and is forced to rely on the goodwill of local people to remain a fugitive of the law.
