Empire State Airways Cargo Flight 521, bound for Chicago, has crashed into a New York City tenement building. It is the 4th plane that Empire has lost this month. It's owner, Roger Boyle, hires Moro Frost, a.k.a. the Scorpion, to investigate.

The man behind the attacks is Garro Kalaydjian, a shipping czar who deals in transatlantic cargo. Using a device that focuses sound, he is able to kill pilots. A higher dose destroys the engine causing the plane to crash. The destruction is not yet over.

Several days later, Empire State Airways Flight 81 for Toronto is to be piloted by the Scorpion. Minutes after takeoff, over a nighttime Manhattan, a plane approaches. The Scorpion is under attack. Not expecting the cargo ship to attack, they prove no match for the Scorpion and are blown out of the sky. The two pilots manage to survive by ejecting from the plane.

The Scorpion's assistant, Ruby, has been trying to dig up information on who is responsible for the attacks. Her eavesdropping lands her in trouble. It takes three men to overtake her. At that moment, the Scorpion arrives, making quick work of two of the thugs. After interrogating the remaining thug, he learns that Kalaydjian is behind the attacks on Empire Air.

News of the Scorpion's involvement spreads quickly. Kalaydjian wants no part of him. The two pilots who ejected over Brooklyn feel differently. They kill Kalaydjian for backing out and plot to kill the Scorpion.

The two proceed to force Roger Boyle to call the Scorpion's assistant, Ruby, and lure her to the airport. The ruse works as Ruby is held hostage by the gunmen. When learning of Ruby's whereabouts, the Scorpion heads for the airport, suspecting foul play.

Upon entering an empty airport hangar, the Scorpion is attacked. After taking out one of his assailants, he pursues the other, who has started a plane with the intent of bombing the airfield. The plane roars down the runway with the Scorpion in hot pursuit. Gunfire from his pistol finds it's mark as the craft explodes ending the threat to Empire Airways.