Professor Lightburn invents a fantastic new rocket, and he and his son make plans to test it -- but the cruel minions of Doctor Karlo are on the prowl. In this adventure, Prince Planet is faced with the problem of the robot thugs, who walk the cold winter nights doing deeds of cruelty and evil, in the service of greedy Doctor Karlo. Will Professor Lightburn ever test his new rocket? Will Prince Planet rescue his friends from the time bombs set to go off, at midnight?
—MGM