"The Emerald Duck" is the 47th episode of Inspector Gadget.
Having learned that the Emerald Duck, "the oldest Mayan artifact known to exist", is the key to an ancient device with destructive power unequaled even by modern weapons, Dr. Claw orders an over-the-top Mexican bandit named Macho Miguel to steal it.
Inspector Gadget is assigned to retrieve the stolen duck before Claw can do any damage and he sets off for Mexico with Penny and Brain — unfortunately, on a M.A.D. — sabotaged plane. They narrowly avoid certain death when Penny manages to regain control of the plummeting aircraft with her computer book.
Once on the ground, Gadget sets off in search of Macho Miguel (with the help of Miguel himself), who promises to bring him to his secret hideout. This is merely an excuse to get Gadget out of the city and into the jungle to do away with him, but, as usual, things don't go as planned and Gadget (with Brain's help) dodges each assassination attempt.Penny heads off into the jungle as well, and with directions from an old native Indian, hopes to find the legendary weapon before Claw's agent does. A fall from a rickety rope bridge into the rushing river below proves fortuitous for Penny, who manages to swim into a cave that houses the ancient crystal device. However, outside the cave, Miguel has placed the green statue into the receptacle that activates the weapon, and it immediately begins firing. Seeing its dangerous power first-hand, Penny intends to destroy the device with a blast from her computer book's laser. Instead, the device goes haywire, sending off bolts of energy in all directions. It finally self-destructs, but not before crippling the M.A.D. jet and sending Macho Miguel right into Gadget's custody as Chief Quimby arrives.