A mad scientist comes along and demands that the Italian government pay him a ransom if they don't want the Leaning Tower of Pisa destroyed by an earthquake. He has a device for generating artificial earthquakes that he plans to use. The government meets his demands, but Lupin has it in mind to take the money for himself. Zenigata chases Lupin into the enemy's lair, and, thinking that the Italian government defied his orders, the criminal hits the switch that activates the machine. Lupin tampers with the machine, however, and it explodes.