The Bigtrees have grown up in the Southwest tip of Florida--in the Ten Thousand Islands--where they have run a unique theme park, Swamplandia. With the exception of Ossie, all of the family members are alligator wrestlers. The star attraction is Ava's mother who dives in a pool of seths, their pet name for alligators.
Their successful business collapses when their star dies of cancer, leaving the business in debt.
Poor Ava Bigtree has been abandoned by her mother; her father; her brother; and her sister, who eloped with a ghost.
No wonder she befriends the Bird Man and jumps at the chance to find Ossie in the Underworld, which coincidently is in the Florida swamplands.
Ava mostly rescues herself by running away from a dangerous situation and the alligator infested swamp. The second rescue in which Kiwi Bigtree, navigating a plane for the first time, rescues Osceola strains credulity. The reunion of the Bigtrees, however, at the Bowl-a-Bed hotel is too good to miss.