Barely surviving the explosion, the Young Allies scramble out of the arsenal and spot a huge opening of a pipe leading underground, and out of the pipe suddenly emerges a huge Japanese invasion force. Toro takes to the air to alert U.S. forces and a battle royal ensues, resulting in the Khan's death and a rout of his forces.; Without knowing it, the Young Allies run into and are trapped by the Khan, a man desiring to become master of the western hemisphere, and involved in the planning stages of a Nazi and Japanese take-over of Alaska.; Believing the Young Allies destroyed, the Khan and his men move on toward Alaska (via Canada by train).; Trapped in a swampland area, a plane spots the boys and transports them to the Yukon for medical assistance. The Young Allies, upon their recovery, buy a cheap car and head out to find their adversary, who already knows they are in country. They are captured and taken to the Khan's huge secret Alaskan underground airport.; The Khan begins his invasion of Alaska, and the Young Allies escape from the secret airport and head for Alaska to alert U.S. defense forces of the impending attack. While there, they confront the Khan inside a U.S. arsenal that is suddenly hit by bombs from an Japanese plane!; A crooked diamond expert is refused citizenship because of his many convictions for jewel robberies and threatens revenge by stealing vital industrial black diamonds.; The true story of U.S. AAF Captain Kelly is told, including the heroic sacrifice of his life, when he rammed his plane into the Japanese Battleship Haruna off the coast of Luzon.; Casey succeeds in ferreting out the true killer of Baldy Bean: a phony Police Commissioner.; Casey is awarded a medal for solving the murder of Baldy Bean, then spots a suspicious beautiful girl. He follows her and breaks into an apartment she enters and falsely arrests her and some other card players!; Casey is ordered by the commissioner to bring in parolee Killer Diller, not knowing that he was awarded a prize while in prison for a true story he wrote.; The police commissioner is livid with Casey for rounding up a ring of counter fitters, believing them to be counterfeiters!; When Big Dope is released from prison, Casey tails him, suspicious that he will go back to his previous career in crime...but the joke is on him!