The Incredible Hulk, Vol. 1

Kang has found a way to prevent the creation of the Avengers. In 1917, one of Bruce Banner's forefathers was saved by the Phantom Eagle. If Kang defeats the Phantom Eagle first, Banner will never be born, and the Avengers will never form. He tries to do the deed himself, but in intense time storm blocks 1917 which he cannot withstand. Instead, he travels to 1971, and offers Hulk the chance to defeat Bruce Banner instead. The Hulk gladly accepts.