In 1973, the first manned expedition to Mars is marooned; by the time a rescue mission arrives, there is only one survivor: the leader, Col. Edward Carruthers, who appears to have murdered the others! According to Carruthers, an unknown life form killed his comrades during a sandstorm. But the skeptical rescuers little suspect that “it” has stowed away for the voyage back to Earth…

A stone-encrusted body is unearthed at Pompeii, and people left alone with it keep dying of crushed skulls…