The Justice League of America, in their second-ever appearance, face the "Challenge of the Weapons Master!" The fame of the JLA's exploits has spread not just across the Earth but throughout the ages. In the far-future year of 11960, the arch-criminal Xotar is unsure which of his fantastic weapons to use to make his last stand against the interstellar police. Having read an entry in Wonder Woman's ancient diary that says he traveled into the past to battle the JLA, he does just that to find out which of his weapons was the one that defeated the World's Greatest Heroes.