When Spencer Gill, Jack Turnbull and Angela Denholm were taken by the Castle in Scotland - when they played Sith of the Throne's monstrous multidimensional game to stay the execution of Earth, and won - they made a deadly, devious enemy of the alien master of The House of Doors.

Now Sith is back, and his game is more deadly yet. In worlds that are known, and others beyond imagining . . . in mad machine worlds, and some that can only be the product of a diseased mind - indeed, in one such that is a diseased mind - Sith's new game will be played out to the bitter end. For the game is rigged, The House of Doors inscrutable as ever, and its doors all designed to lead Gill and his companions ever deeper into worlds of uttermost terror . . .