Avengers Vol.1 #100
Bringing warning of impending doom, an amnesiac Hercules is captured by Ares, prompting the Avengers to call out for aid from all their members, past and present. Traveling to the Black Knight's castle for aid, all the members arrive, including the Hulk who is convinced to join their fight. The group enters the Black Knight's castle where in the basement Dane summons the spirit of his ancestor, the original Black Knight, who reveals to them the chain of events that brought all of them together; The group splits in two, one group remaining on Earth to battle any Olympian invaders, and the other to travel to Olympus to free Hercules and stop Ares.
Printed: Jun 1972
Writers: Roy Thomas
Art: Barry Windsor-Smith, Joe Sinnott, and Syd Shores
Cover: Barry Windsor-Smith