Earth's Mightiest double-sized anniversary issue! A time traveler from the future slams into the present to witness - the last adventure of the Avengers?! Who's responsible for this tragedy? Maybe the gang of classic foes who strike in this awesome adventure! Plus: a surprise guest appearance that throws this title into the Onslaught war! "The Crossing" is over, and now Mark Waid and Mike Wieringo invite new readers to join the Avengers as they embark on a new era!