Tomorrow's Guardian, by Richard Denning, is the story of a boy named Tom Oakley who discovers that he can "walk" through time. His job as a "Walker" allows him to go back in time and save other Walkers. Unfortunately, a dimension parallel to ours, where the Nazis rule, wants to control Tom's world as well. The story takes the reader from a sinking U-boat to the Great Fire of London, from a Nazi- controled England to a Zulu vs. English battle.