The former adviser to the long-deposed King of Venus plots to return the despot's son to power by use of the Z ray, a mind-controlling device, and a time-traveling spaceship which allows the two men to rob banks and disappear into the past. Commander Corry and Cadet Happy take the only rocket in the Space Patrol fleet with time-traveling capabilities and pursue the criminals back to the 20th-Century. (thetvdb.com)