Facing foreclosure of their homes in the Goon Docks area of Astoria, Oregon, to an expanding country club, a group of children who call themselves "the Goonies" gather for a final weekend together at the home of Mikey Walsh.
Rummaging through the Walshes' attic, they come across a 1632 doubloon and an old treasure map leading to the famous pirate "One-Eyed" Willy's hoard located nearby. The kids make their way to a restaurant on the coast that coincides with the map and discover the restaurant is being used as a hideout by the criminal Fratelli family. The Goonies find an underground tunnel described on the map and follow it. The Fratellis find out that the Goonies are going in search of treasure and follow them.
The Goonies evade several deadly traps along the tunnels while staying ahead of the Fratellis. Ultimately, they discover the treasure only to be confronted by the Fratellis who demand that they turn over their loot to them. The Goonies escape while the Fratellis set off a trap that causes the collapse of the Grotto. Barely escaping with their lives, the Fratellis are captured by the police.