Troubled Martin Clegg has always suffered from dreams which seem intensely real. In them, bizarrely, he's another person not of this Earth! He's finally forced to confide in his fiancée, Elsie Barlow, and they consult Martin's scientifically inclined friend Tom Cavendish. He reveals, astonishingly, that Martin has a cosmic twin on a planet of Betelgeuse to whom he's mentally linked. Unsuspecting, they are both about to become caught up in the strands of an incredible cosmic mystery in which, to save the universe from destruction, Martin must die--twice!