A group of alien botanists secretly visit Earth to collect specimens of plants in a Californian forest. When government agents appear on the scene, the aliens flee their spaceship, but one of them is left behind. A ten-year-old boy named Elliott discovers that something is hiding in their tool shed: it is the alien who escapes after being discovered. Elliott leaves the candy to lure the alien to his home and with Michael and their five-year-old sister, Gertie, they decide to keep it hidden. The alien demonstrates its power, through its bright tip, healing a small wound on Elliot's finger. At school the next day, Elliott begins to experience a telepathic connection with the alien, including signs of intoxication (because the alien is at home, drinks beer and watches television).