For their fourth big-screen outing the crew of the USS Enterprise abandon their usual 23rd century time frame for Earth in the year 1986. In order to save the planet from a rogue space probe in the future, Kirk (William Shatner), Spock (Leonard Nimoy), Bones (DeForest Kelley) and co must travel back to the twentieth century to find the only creature capable of communicating with it: a whale. The story is given comic treatment - Spock hides his Vulcan ears with a headband and poses as a burnt-out hippy, while the normally intrepid Kirk gets lost on a bus.