Professor Gizmo, a master criminal, devises a plan to use Spider-Man to attach an antenna to a sunken treasure ship, the El Conquistador, since only he can withstand the pressure at that depth. Peter, meanwhile, has been invited to a charity cruise on board Jameson's yacht. Gizmo attacks the yacht and demands that all the diamond donations be surrendered to him, using the old ship, the Monitor. Failing to draw out Spider-Man with the theft at sea, Gizmo then attempts to steal the Spirit of St. Louis from the Smithsonian Museum. This time, Spidey shows up save the plane, but is blamed for the subsequent theft of it. Next, Gizmo uses a remote control device to control various machines in the city, and steals a bank's vault contents. Gizmo then announces that he will return the stolen diamonds, money and plane in exchange for Spider-Man. The next day, during the Thanksgiving parade, Gizmo captures Spidey, and tells him of his plan to raise the treasure ship. After Spider-Man is forced to raise the ship, he has to stop Gizmo and recover the stolen items.