Bruce Banner goes to a monastery in the Himalayan Mountains to meet with a monk known as the "ancient one" to learn how to control his transformations. The monk suggests that Banner go see Dr. Strange. So Bruce, Rick Jones and Monkey arrive in Greenwich Village in New York to meet Strange.
While Rick is amazed at the magical abilities of Strange, Banner is not. Strange tells Banner that he might be able to free him from the Hulk by going into another dimension and separating him and Hulk and trapping the Hulk in a section filled with beings called the "mindless ones" who are always battling within a barrier which confines them.
Strange then opens a rift into another dimension and are faced with a being called Dormammu. Dormammu needs a host body to attack, so he tries to possess Banner. But Bruce changes into the Hulk. Strange covers the Hulk with his magic "ribbons" (Bands of Cyttorak) so Dormammu cannot possess the Hulk. Dormammu then tries to possess Rick but Strange protects Rick with his magic ribbons also. But Dormammu informs them he doesn't need a human host, so he possesses Monkey. The Dormammu/Monkey grows into a giant monkey and attacks them. The fight goes on for a while until Strange separates Banner from the Hulk.
Banner now in spirit form has the ability to grab Dormammu's spirit and pull him out of Monkey. Hulk, seeing Dormammu, grabs him and throws him into the barrier with the mindless ones. But before Strange and company can go back to our dimension, Dormammu casts a spell on Banner so Strange cannot use his magic to cure Bruce from being the Hulk. Strange feels badly about all this but Bruce still has hope that one day he'll be cured.