The game begins in a dream sequence, where a man, Bruce Banner (Eric Bana), transforms into a large and powerful monster, dubbed the Hulk, and destroys waves of soldiers and tanks sent by the military to destroy him. Upon awakening, Bruce Banner is contacted by his old mentor, Dr. Crawford, who explains that he has developed a cure for the Hulk called the Gamma Orb, but military troops (led by the corrupt General John Ryker) have raided the lab.
Bruce Banner sneaks into the lab, and discovers that General Ryker wants to obtain the Gamma Orb. After reaching Dr. Crawford, Bruce allows his old mentor to use the Gamma Orb on him, but Crawford uses it to steal the Hulk's energy. Crawford touches the Orb and absorbs a part of Bruce Banner's power, transforming himself into a Hulk-like creature called Ravage. Simultaneously, Banner transforms into the Hulk.