When the White Guardian appears uttering a cryptic warning of imminent danger - "The winner takes all", the Doctor is puzzled. Then the TARDIS materializes on an old Edwardian sailing ship. Before long, however, he is amazed to discover that the ship, along with others, is sailing through space.

The Doctor and his companions soon become caught up in a sailing race run by the mind-reading Eternals. The first prize is Enlightenment - ultimate wisdom to gain one's heart's desire, and some of the more devious crews will stop at nothing in order to claim it. But as the Black Guardian's evil mesh draws tight, it looks as though the Doctor might not live to cross the finishing line...