Las Vegas cab driver and ex-crim Jack Bruno is trying to stay out of trouble. But when teenage brother and sister Sara and Seth appear in his cab out of nowhere he embarks on the adventure of his life. Realising they are far from ordinary, Bruno, along with UFO expert Dr. Alex Friedman, soon find themselves helping the extraterrestrial siblings escape the clutches of an evil organisation as they make their way to Witch Mountain, a secret government outpost in the Nevada desert. It is here Sara and Seth hope to return home – saving Earth in the process.