While Hank Pym has invented a new gas mask made out of unstable molecules, armored cars in the city are being besieged by a criminal dubbed the Hijacker, who is able to steal entire armored cars and make the drivers forget what happened. Heaviest hit by this is Howard Mitchell, owner of the Mitchell Armored Truck Company, who is losing clients every time one of his armored cars is stolen.
Hearing of Mitchell's plight via his spy ants, Ant Man pays Mitchell a visit and agrees to help try and catch the Hijacker. Before leaving, Ant Man takes note that Mitchell happens to have a collection of ancient Inca carvings.

Arriving on the scene, Ant Man's presence gives the guards on site a sense of relief until Ant Man is stricken with appendicitis and orders his ants to carry him to a hospital. Feeling as though Ant Man had failed them, the guards continue on their armored car rounds anyway.
As expected the Hijacker attacks and uses a gas to knock out the truck drivers. As he is using a blow torch to access the money inside the truck, Ant Man suddenly attacks! In combat, Ant Man explains that he has a suspicion that the robberies were an inside job so he feigned illness to give the Hijacker the courage to make the theft, while Ant Man hid on the roof of the truck (using his gas mask to render him immune to the gas.)
Eluding his opponent in the interior and engine of the truck, Ant Man manages to land on his foes gas-mask and tear a hole in it big enough for the Hijacker to be effected by his own gas, causing him to pass out. Ant Man orders his ants to unmask his foe, revealing him to be Howard Mitchell. When the police arrive, Ant Man explains that he was tipped off that Mitchell was the crook because the statues in Mitchell's office tipped him off about what he knew about the Inca use of sleeping vapors that cause memory loss. Defeated, Mitchell reveals that the reason why he committed the robberies was because his company was losing money and his thefts would recoup the losses, however he never figured Ant Man would ever get wise to his plot.

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