A brilliant military scientist creates a revolutionary serum that transforms him into a massive, purple, superhuman mutant, and fights for the love of the woman he longs to marry while being forced to do battle with an evil scientist threatening to destroy the moon. Henry Howard is on the verge of a massive scientific breakthrough when he decides that it's finally time to propose to his girlfriend Hannah. Though Hannah's father General Darwin has strictly forbidden the romance until Henry's experiments yield actual results, the rebellious young scientist buys an engagement ring, and prepares to pop the question. But just as he's about to do so, a mugger appears and makes off with the ring. Enraged, Henry injects himself with the serum and becomes a giant creature driven by rage. Later captured by a detective and forced by Darwin to prevent the villainous Dr. Kantlove from launching nuclear weapons aimed at the moon, The Incredible Bulk becomes the only creature capable of preventing a disaster that could alter the course of human history.