Thirteen is not a number, it is a state of mind. Thirteen is the story of Stephen Bardot, a taxi driver working on the night shift in Brighton. He works such long shifts that he is often driving while exhausted, and it is then that he starts to experience major alterations to his perception of reality. People start to take lifts in his cab who know things they shouldn't, and who ultimately may not even be real, although the question of what constitutes reality forms one of the basic themes of the novel. He regularly gives lifts to Valerie - beautiful, haunting, but terminal - from 13 Wish Road to her 'positive thinking classes' at the Cornerstone Community Centre on Palmeira Square. When he is no longer asked to collect her, he fears that she is dead, and queries this with Sal, one of the night operators. Her response turns Stephen's world upside down. 'But Stephen,' she tells him, 'there is no such address. Wish Road doesn't have a number thirteen.' She's right. Wish Road's odd numbers are 7, 9, 11, 11a, 15, 17...And number 11a looks totally different from the house he thinks of as number Thirteen. So where has he been collecting Valerie from all this time? A house that doesn't exist? As time passes, the world gets weirder. People appear (and disappear) who know far too much about Stephen and his past, and who lure him further and further into the twilight world of Thirteen. But if he asks any questions, he gets hurt. Ultimately, he decides, for the sake of both his safety and his sanity, he must walk away. But Thirteen has no intention of letting him go...