Spun from Daniel DeFoe's tale of the titular character, Commander Chris Draper (Paul Mantee) and Colonel Dan McReady (Adam West) are orbiting Mars in an exploratory surveyor. A malfunction forces them to eject, with only Draper and a monkey named Mona making it out alive. The two safely land on Mars and must figure out how to breathe, drink, and eat on the hostile planet. After some time, Draper crosses paths with a human, Friday (Victor Lundin), who has recently escaped slavery on an alien planet. As the two find a means of communication, they become friends, and work together to survive incredible odds.