Hulk's departure from the Avengers caused a rift that led to the end of the Avengers, since they felt they couldn't go after him. Stark contacts Rick Jones to find the Hulk, while Thor went back to Asgard and Jan and Hank went back to being "normal" people.
Like in Earth-616, Rick locates the Hulk and goes after him on his own, and is being held hostage when Stark goes to rescue him. They barely survived the Hulk encounter, and managed to make it back to the Mansion.
Also like in Earth-616, Namor and the Hulk teamed up and challenged the Avengers to a fight to the death, though in Earth-776, the Avengers were disbanded. Stark accepts the challenge, and builds Iron Man armor for Hank, Jan and Rick so they can all stand up to the Hulk and Namor together.
He introduces the armor to the other three, who can't control themselves in it, and decide to stay in retirement instead of wearing the armor, much to Stark's dismay. Alone again, he overrides the limits of his own armor, and transfers more than the maximum amount of energy into it, setting him up to fight one final ultimate battle.
