Hailed as a hero for his victory over the Hulk-Killer Android, Hulk is granted a full amnesty by President Lyndon Johnson.
Boomerang, hiding in the shadows, hurls an explosive disc that provokes the Hulk who starts running amok in a rampage through the streets of New York city.
Thunderbolt Ross, believing the Hulk is still a menace, destroys the amnesty order, and resumes his pursuit of the monster.
Meanwhile, Boomerang intercepts the Hulk in the mountains and pelts him with explosives, and tranquilizer gas. Even drugged, Hulk is stronger than his foe, so Boomerang destroys a nearby dam, flooding the canyon where the Hulk is waiting. Hulk creates a sonic boom, knocking his enemy out of the air.
Gas causes Hulk to transform into Bruce Banner who tries to rescue his foe but without the Hulk's strength, is unable to hold onto Boomerang who plummets into the flood waters.