Justice League of America #9

In "Crisis on Earth-Prime!: Let Old Acquaintances be Forgot…", the Justice Society of America and the All-Star Squadron face a dual threat from Per Degaton and the Crime Syndicate, unraveling a timeline fracture that threatens both Earth-2 in 1942 and Earth-Prime in the early 1960s. With the fate of two realities hanging in the balance, heroes from different eras must unite to restore order—only to find that their victory comes at the cost of memory, as history rewrites itself and their greatest battle is erased before it ever happened.

Martian Manhunter returns to Earth with a dire warning: Mars II is preparing to invade, led by a rogue military commander known as The Marshal. As the United Nations faces an ultimatum delivered by The Marshal’s cold, relentless robot servant, Challenger, the fate of Earth hangs in the balance.