Invasion of the Star Creatures is a science fiction comedy about two U.S. Army privates, Private Philbrook (Robert Hall) and Private Penn (Frankie Ray), who are sent on a mission with their squadron to inspect a recently discovered cave near the base. Philbrook and Penn become separated from their squadron and are attacked by strange creatures. The two are held hostage and brought to a spaceship where they meet alien women from the planet Chalar. Dr. Puna (Delores Reed) and Professor Tanga (Gloria Victor) explain to the pair that they plan to take over Earth. Philbrook and Penn realize that their squadron has also been kidnapped by the aliens. The privates discover that kissing the aliens makes them powerless. They spend a brief time testing this theory and manage an escape from the spacecraft. They return to the army base and try to save their squadron and the Earth from the alien attack.