A car accident leaves Robert Maitland, a wealthy architect in the midst of concealing his affair with a colleague, stranded in a large area of derelict land created by several intersecting motorways. Though surrounded by motorists and within sight of large buildings, Maitland is unable to escape the median strip and must struggle for survival. Along the way he encounters other inhabitants of the median strip, which he comes to call "The Island," including a teenaged sex worker who hides out in an abandoned air-raid bunker and an acrobat who became mentally disabled in an accident and now salvages car parts for bizarre shamanic rituals. He learns to survive by scavenging discarded food from littering motorists, and eventually comes to think of the island as his true home. Conflicts ensue with the other inhabitants and before long Maitland is struggling to determine whether he was truly meant to leave the island at all.

The novel heavily references Shakespeare's The Tempest, with its remote island setting, its stranded inhabitants, the belief in sorcery and its Caliban character, the unstable acrobat.