APPEARING INSIDE THE TARDIS, THE WHITE Guardian delivers an enigmatic warning: “Must not win… winner takes all.”
Soon afterwards, the TARDIS materialises in the hold of what appears to be an Edwardian sailing vessel called the Shadow. While the crew members below deck allude to various mysterious features about the voyage, the enigmatic officers prove hospitable, treating the Doctor, Tegan and Turlough as honoured guests. It transpires that the ship sails not on the sea but in space, engaged in a race around a course marked with planets as buoys. The ship’s officers are Eternals from beyond time, using abducted humans to crew their vessels.