The express rocket is leaving for Pluto and astronauts Morrey, Serge and Tony are boggled by a concept that's old stuff to any kid who's read Heinlein--""The mathematics boys are still working on it . . . I know it sounds crazy, but they believe that if you could travel at the same speed as light, time would stand still."" Soon enough, the projected ""time slip"" becomes the least of their problems. Their fuel tanks are punctured by a meteor, their ship is drawn inevitably closer to the mysterious, super-density Planet X, and the only hope lies in a singlehanded rescue attempted by their old buddy Chris who comes dashing out to Pluto in a spare spaceship. Thank God, Tony takes his revenge on Planet X, blowing it up as all concerned are ready to head home and thus saving our solar system from being sucked up into its ever increasing mass. Stiff and affectless hot-dog heroics . . . forget it.