Mikey Walsh (SEAN ASTIN) is glum about the future. And that's because it involves moving out of his home with his family and separating from his group of friends, who call themselves the Goonies, as they're considered outcasts by the higher social class that seeks to turn their homes into a large golf course. His mother doesn't see any way to raise the money to stay, but Mikey does, when he discovers a map in his attic leading to the treasure of a pirate named One-Eyed Willy. And that treasure is somewhere underground, not too far away from their homes.
He heads to a restaurant boarded up for the winter with Chunk (JEFF COHEN), always eating, always nervous and always clumsy; Data (JONATHAN KE QUAN), an ingenious budding inventor; MOUTH (COREY FELDMAN), who always has something to say; and his brother Brand (JOSH BROLIN), following the map and hoping that what may be found is enough to keep them from having to move.
Joining them is Andy (KERI GREEN), whom Brand likes and hopes the feeling is mutual, and Stef (MARTHA PLIMPTON), Andy's friend who's not at all fond of Mouth, and is reticent about the adventure. They encounter the Fratellis, Mama (ANNE RAMSEY), Jake (ROBERT DAVI), and Francis (JOE PANTOLIANO), who also seek the treasure. Through an intricate cave system they will all go and encounter the clues and booby traps left behind by One-Eyed Willy.