The narrative centres on the intersection of Toshiko's romance with Tommy Brockless (Anthony Lewis), a cryogenically frozen soldier from World War I, and a number of hazardous time slips from 1918. As the impending crisis becomes more severe, Toshiko must choose between the man she has fallen in love with and the world at stake. Tommy eventually elects to return to 1918, where Toshiko knows he will be executed because of his shellshock.
