The fate of the planet in the hands of Larry, Moe and Curly Joe? That's exactly the situation the trio finds themselves in when they befriend a wacky scientist and must defend his secret invention from a pair of malevolent Martians. Sight gags, slapstick and plenty of nyuks abound as the Stooges bumble their way through an adventure of intergalactic proportions.

Three druggists travel with a Milquetoast inventor, Schuyler, and his girlfriend, Diane, to ancient Greece on a newly invented time machine. There, the evil tyrant, Odius, takes a shine to the woman and has the guys enslaved as galley rowers using the excuse of the three druggists helping a rebel leader, Ulysses, escape. The rigors of the rowing pump Schuyler up into a muscleman with strength comparable to Hercules himself, who is in the employ of Odius. The threesome get the idea of raising money by promoting Schuyler as Hercules for a series of physical contests. Using a combination of his great strength and, a judicious use of a large supply of potent tranquilizers Curly-Joe brought with him, Schuyler is a success. However, this leads to trouble when the real McCoy learns about the imposter.

The Stooges are janitors working at a space center who accidentally blast off to Venus. They encounter a talking unicorn, a giant fire breathing tarantula, and an alien computer who has destroyed all human life on the planet and creates three evil duplicates of the Stooges. When the boys return home triumphant, they are given a hero's welcome.