A family of aliens lands on earth, but leave their child here accidentally when they have to immediately leave. The frightened child alien (E.T.) wanders into the yard of a young boy (Elliot) and his family. Frightened at first by E.T., Elliot ventures out into his backyard to befriend the creature. He brings it into his home, sharing it with his brother and sister but keeping it a secret from his mother. Elliot and E.T become really close, but Elliot knows that E.T. really wants to go home to his family. Together they build a machine to contact E.T.'s parents. They receive it and plan on coming back to earth.
Before they come though, the government (who had been watching Elliot's house for a while) break in and confiscate E.T. They turn the house into a science lab, doing numerous experiments on E.T. and Elliot. E.T. dies, but because of the connection that the two share, Elliot's sorrow over his friend's death brings E.T. back to life. Elliot and his brother hijack a medical van and drive E.T to the woods to meet his parents. They find the spaceship and E.T. reunites with his parents and has to say goodbye to his new earth friends.