During World War II, President Roosevelt is asked by Colonel Steve Trevor to get the United States involved by creating a team of superhumans. Consisting of Trevor, Black Canary, Hawkman, Hourman, Jay Garrick / Flash, and led by Wonder Woman, the Justice Society of America is formed.
In the present, Barry Allen and Iris West picnic in Metropolis, hoping to get away from "work". However, their plans are disrupted by Superman fighting Brainiac. Allen comes to Superman's aid as the Flash. When Brainiac fires a Kryptonite bullet, Flash tries to catch it, but runs fast enough to channel the Speed Force for the first time. Guided by someone's voice, Allen arrives in what he believes is the past during a battle between the JSA and the Nazis. Despite initial confusion over his allegiance, the JSA realizes Allen is an ally and seemingly comes from the future. As the team mobilizes to stop another wave of Nazis, Allen takes Trevor back to the JSA's base and learns about the team, whom he never heard of before.
