After years of pursuing a jazz career that never quite took shape, Mark Deveraux took several jobs writing TV Show themes and commercial jingles to earn a living; while very successful in acquiring steady work, he longs to write meaningful music. After winning out over several more experienced composers to score a sci-fi film, he spends a weekend in a cabin trying to develop a song that sounds like a 'universal greeting' based on the producer's instruction. Finally composing something that he believes is worthwhile, he calls his girlfriend, who is the producer for an internationally syndicated talk radio show, who accidentally broadcasts the song.
The following day, while recovering from a hangover, Devereaux is visited by a Martian who claims that they heard the greeting and have come to Earth to establish lasting peace and prosperity on the planet—only to immediately recant and state that he was joking. He claims that "Mars is a dump" and that the billions of bored Martians have decided to come to Earth and to have fun at humanity's expense. Devereaux tries to shoot him, but discovers that the Martian has the ability to both read minds and teleport, allowing him to predict and dodge any attack. Around the globe, billions of Martians begin to wreak havoc with their abilities, revealing intimate secrets, appearing and disrupting major sporting events, and voyeuristically spying on couples who are having sex (as they cannot reproduce sexually).
Deveraux realizes that they felt 'invited' by his music and interrupts another national broadcast to play the song again—realizing too late that he needs to play it in reverse. Feigning insanity, he is committed to a psychiatric hospital where his girlfriend eventually breaks him free. Trying again, they hijack another international broadcast while Devereaux plays the song backwards. In spite of numerous distractions and ploys by the Martians, he succeeds and the Martians simultaneously disappear from around the globe. Having realized that he has talent, a short time later he quits his jobs for Hollywood and reforms his Jazz quartet to go on the road.
