During World War II, the Flash (Barry Allen) inadvertently travels back in time due to a fight with Brainiac, finding himself in the midst of a battle between Nazis and the Justice Society of America (JSA), a group of superheroes aiding the Allied forces. Uncertain of how to return to his own time, he joins forces with the JSA, which includes Wonder Woman, Hawkman, Hourman, Black Canary, and team leader Steve Trevor. Together, they undertake a mission to discover and thwart Nazi plans involving a mysterious artifact that could turn the tide of the war in favor of the Axis Powers.

The mission takes them across enemy lines as they face off with formidable foes and encounter the challenges of war-torn Europe. The Flash learns valuable lessons about heroism and sacrifice from the seasoned veterans of the JSA, who are determined to help the Allies win the war at any cost. As they attempt to unmask the secrets behind the Nazi's powerful artifact, the team dynamics and the individual members' resolve are put to the test. The Justice Society must navigate treachery, face moral dilemmas, and battle the enemy to ensure the artifact does not fall into the wrong hands. Meanwhile, relationships within the team grow, as the Flash hopes to find a way back to his own time, and perhaps alter the course of history itself.