Trosclair ignores his father's warning about Gargantua, the rogue alligator living in nearby Bayou Fontaine, and heads off into Bee Island Swamp to hunt for turtle eggs.

A boy's heritage from his dying grandfather, who protects the alligators of their Louisiana swamp from poachers, is the knowledge of the ways of the swamp and how it should be kept undamaged. Includes informational pages on alligators and swamps.

When his father takes him to visit the Louisiana bayou, Buster sends postcards to his friends back home telling them about the Cajun language, learning to catch crabs, and keeping watch for a swamp monster.