While working for Mr. Howell, Gilligan unearths a chest. The castaways think it must contain a pirate's treasure. When ownership of the chest is disputed, the case goes to court, with the Professor presiding as judge.

Gilligan discovers a jungle boy living on the island. He shows them a hole in the ground that causes objects to float, and the professor theorizes that it is expelling either helium or hydrogen. He immediately sets to work building a large balloon, with the hopes of carrying one of them back to civilization.