Beautiful alien Amazonian women plan to conquer the world using an army of vegetable monsters. Dim-witted privates Philbrick and Penn bumble into a cave in search of atomic activity but collide instead with fierce carrot-topped tree mutants and their leaders, the 7-foot space sirens Prof. Tanga and Dr. Puna. This lavishly low-budget sci-fi romp has the bodacious aliens planning to overrun Earth with their vege-men army, but first they want the G.I.s to explain the meaning of love.

Phil, a part-time truck driver and singer who wears his pants far too high, meets a feisty platinum blonde who challenges him to a drag race through Griffith Park. When he is caught and loses his license, he meets up with the sketchy Frank Wooster who offers him a job singing in his new nightclub. When Phil discovers that his new job also includes drug running, he must fight to save his friends and himself.