Little Elliot (Henry Thomas) found a lost little alien. He quietly took him in and introduced him to his brother and sister. The children got along with the alien in a friendly way, fed him chocolate, took him to the suburbs to look for traces of his family, and were excited about the little alien's special abilities. Gradually, Elliot and the alien formed a wonderful connection, overcoming the barrier of verbal communication. But soon, the existence of aliens was known to the adults, and a ruthless hunt was launched. ET was captured and taken to the laboratory, and little Elliot fell ill. The children were angry, and they spontaneously organized to rescue the alien. Elliot also woke up under the inspiration of his heart and joined the rescue operation. Can they succeed?