Colonel Nozzaire is a budding archeologist and author who has just written a book about the Aztecs. Too bad nobody's coming to his book launch except Gadget with news from General Sir. A recent earthquake in Mexico unearthed the entrance to the lost underground Aztec City of Gold. Rumor has it the Aztecs hid their "Crown of Invincibility" in the city and it's a prime target for MAD so WOMP has to find it before Dr. Claw uses it to become unstoppable. Colonel Nozzaire, Gadget, the Gadgetinis and an Archeologist descend into the city while Penny's left back at the base camp. She overhears assistant archeologist Ron Limond talking to Dr. Claw about how he found and hid the map to the secret entrance & shortcut tunnel that avoids all the traps. He heads off to the City and Penny breaks into his safe to find the map but Ron returns to pick up the crowbar he forgot and catches her. Ron forces Penny into the secret entrance tunnel and beats Gadget to the underground city's treasure vault.