Dr. Brown (Christopher Lloyd) always has some bizarre inventions. While testing the time machine he invented, he enlisted Martin (Michael J. Fox), a high school student who has forgotten his age. Unexpectedly, the doctor was killed by gangsters during the experiment. Martin fled with a time machine in a panic and returned to 30 years ago. Martin meets his father George (Crispin Glover) and mother Loren (Lea Thompson) 30 years ago. While looking for Dr. Brown from 30 years ago so that he could return to the future, Martin tried to match George and Lorraine so that he wouldn't disappear in the future. But George was weak, and Martin self-defeating in the matchmaking process, which made Lorraine fall in love with her. There was also the annoying Bev who interfered with him, which made Martin angry. Martin is struggling between his parents, and he has to find a doctor as soon as possible and find a way to return to the future...