Peter Simon a Christian welfare worker is wracked by anger, guilt and fear induced by the reemergence of a childhood nightmare. He is beset by doubts and the futility of his vocation, even the loss of faith, when he meets Beatrice Rankin on a stretch of highway. Driving to her camp, they survive a plunge through the surface of a road hundreds of metres below ground. Trapped, they discover a huge bored hole down in the earth which is their only means of escape. Descending, they are nearly killed by blasting snow and ice. Finding a side passage they enter a bewildering and extensive series of tunnels. It is there that they meet an evil being: Elymas, Lord of Dis. They are told by Elymas that they are in Dis to face a series of trials set by a pact between God and Satan with no guarantee of survival. Peter is to protect Beatrice from harm and complications arise when Peter concludes that the experiences and dangers they face are from his imagination, sub-conscious or from situations in literature he has read. Beatrice is sceptical and thinks he is mad but comes to trust him. Another disturbing aspect of the journey for Peter Simon is that his underlying, largely suppressed fury, is unleashed in Dis. Episodes are connected by the childhood nightmare when he is out of control, particularly when Beatrice is threatened. As their friendship grows and blossoms into love, they fight against Elymas and the savagery of his evil world. Will Peter Simon and Beatrice Rankin survive?