Bruce has been dying of ALS for a long time now. Doc Samson, along with Reed Richards, is trying to cure him but there seems to be nothing they can do. While Banner’s mind dies, the various Hulk identities remain strong. They take over his body, leave the medical facility, and stumble across the hideout of The Leader.
Leader has been dead for a while, too—in an explosion. But Hulk finds some monsters are rebuilding his gamma-powered body. Leader says he wants to cure Banner because he feels a kinship with the gamma monster’s host. Hulk gets the cure, and watches as the rebuild of Leader’s body fails and Leader seems to die (again).
Hulk then takes the cure to the Baxter Building, where he argues with Thing about who is stronger, and then Ant-Man shrinks down, goes into Hulk’s blood, and fixes him up.
And so we find ourselves at status quo once more, so that a new creative team can arrive.
Well done.
To the credit of Marvel, understanding that ALS is one of the most tragic diseases known to man, they offer a PSA at the end–which helps make the oversimplication of Banner’s cure much more palatable.