Louis Gossett Jnr. returns as Ex-Air Force General 'Chappy' Sinclair in the fourth Iron Eagle film in which he starts a flight school for young offenders. During training he and his kids discover Air Force Officers mysteriously moving canisters from an abandoned air base. These canisters contain lethal toxic chemicals used in biological warfare, but no one is convinced of the dangers. Sinclair and his kids must therefore use their flying and criminal skills to stop these canisters being used.