An energetic tale follows a ragged but determined youth who seeks entry to a workshop of young inventors after inheriting a box of plans. He proves himself by helping design and build an electric hydroaeroplane while the team confronts sabotage, stolen plans, mechanical crises, and daring sea and air rescues. Episodes send them to a fair and pit them against dishonest rivals and cronies, testing ingenuity, loyalty, and courage. The narrative balances technical description of devices with brisk adventure, highlighting problem-solving, persistence, and collaborative effort.