New York City. Donald Blake, a surgeon, sits in a bar, dejected, drinking the pain away from losing a patient. A woman, drawn to Blake's suffering, sits down next to him, and engages him in conversation. The Lady Sif enters the bar, and offers Blake his enchanted walking stick. Blake angrily orders Sif to return to Asgard. Blake's poor treatment of Sif nearly incites a bar brawl. Blake furiously returns the walking stick to Sif, who finally departs. Blake leaves with the woman, and spends a drunken night in her bed. Sif observes Blake's amorous encounter with the mortal woman. Upon waking, Blake finds that Sif has placed his walking stick next to the mortal woman's bed.
Blake races up to the rooftop. Flailing the walking stick about his head, Blake angrily rails against his father, Odin. After petulantly rejecting the woman's efforts to comfort him, Blake strikes the walking stick against the ground, triggering his transformation into Thor. Gathering the mortal woman into his arms, Thor gives her an aerial tour of Manhattan. The Lady Sif returns to Asgard. Odin expresses his concerns to the Grand Vizier. Odin fears his son is dangerously close to renouncing his Godhood, that he may live out his days as a mortal man. Sif confirms Odin's fears, while also expressing her belief that Thor no longer loves her. Odin does his best to comfort Sif.
Thor tries to explain his love of humanity to the mortal woman, but his words fall on deaf ears. The woman is smitten with the spectacle of being Thor. Thor leaves the woman, and flies across the city, taking in the full spectrum of mortal life. On his sojourn, Thor rescues construction workers, stops a robbery, and douses a tenement fire. Thor walks the streets of Manhattan, trying to connect to humanity. Thor flies into space, and hurls his hammer away. In sixty seconds, Thor becomes Blake. The hammer, once again a walking stick, returns to Blake. Lacking the fortitude to commit suicide, Blake grabs the walking stick, strikes it against his shoe, and becomes Thor.
Sif confronts Thor. Striking his hammer against the ground, Thor becomes Blake. Blake attempts to show Sif the simple, yet complex, joy of a mortal life. Sif tolerates a host of indignities to appease Blake. Try as he might, however, Blake cannot get Sif to perceive the mortal world as he does. In Blake's apartment, Sif spurns his advances, put off by his frail mortal form. Blake angrily rails at Sif, for not understanding that Blake is not merely a disguise, but the mortal aspect of the god, Thor. Sif storms out. Blake receives an emergency call, to return to the hospital. In the operating room, haunted by the death of his last patient, Blake finds that he cannot perform the surgery to save the child's life.
Sif confronts Blake. Sif reminds Blake that were the child jeopardized by a more physical threat, Blake, as Thor, would stop at nothing to overcome the peril. Blake draws strength from his immortal side, and returns to the operating room. Odin is content that Thor has reconciled his two selves. Odin plots further tests to keep his son in line.