Progress has left Middletown behind. The tin mine is worked out, jobs are scarce, and a crack has opened across the moors that the locals believe reaches into the depths of Hell itself.
But things are changing: Lord Urton is preparing to reopen the mine; the society for Physical Research is interested in the fissure; Roger Nepath and his sister are exhibiting their collection of mystic Eastern artifacts. People are dying. Then a stranger arrives, walking out of the wilderness: A man with no name, no history.