A pair of young inventors build and test an experimental vehicle that can travel by land, air, and water, but a stowaway and later mutiny precede a violent storm that leaves the craft wrecked and its occupants cast ashore. Stranded, they confront sea dangers, survive attacks and predatory animals, and explore a wild coastal jungle where encounters with large prehistoric-like fauna and local tribes complicate their chances of escape. Resourcefulness and improvised engineering drive repeated rescues and discoveries, including a contested find that pits material gain against freedom. The tale alternates action-driven episodes of peril with moments of scientific cleverness and cooperative problem-solving.