Gamera vs. Guiron

Aliens kidnap two children and take them to another planet for the purpose of getting knowledge from their brains, but Gamera follows and tries to rescue them.
Two young boys sneak aboard a spaceship and find themselves whisked away to the mysterious planet Terra. There, they encounter Gamera's old foe Gyaos and two female aliens with a taste for human brains. Gamera must save the children and battle the new monster Guiron, whose entire body is a deadly living weapon.