Chode's Grandpa Bento and his cronies escape from the fun city rest home because, they say, the staff is stealing their brain waves. Chode chalks the crazy charges up to senility and gets the old folks re-admitted. Then he learns that their brainwaves are being stolen to power up a nearby amusement park. While Gus and T'Nuk sneak back into Fun City to break out Bento and his friends, the others work madly to shut down the treacherous brains behind the deadly scheme.