Dr. Don Blake, frustrated that his beloved Jane Foster thinks he is a coward for betraying Thor last issue (unaware that it was a ruse to stop the Cobra and Mr. Hyde), agonizes over his love life. He decides to change to Thor to sort out the problem—just as Jane walks in. Thinking quickly, he tells the startled nurse that he is here to seek revenge on Blake for his treachery. Jane intercedes for Don, revealing that she loves him; Thor makes a promise not to harm the man she loves. Once out of sight, the elated Thunder God flies through the air goofing through sheer happiness. He is seen though by a new enemy, Paul Duval, who is arriving in New York aboard a passenger jet. When the jet lands, Duval is the only one to leave, as all the other passengers have been turned to stone!
Duval helpfully fills us in on his background: he was a lowly chemist in Paris when he spilled an odd chemical on his right hand. He found that anything he touched with his affected hand also turned to stone—starting with his own body. The effect wore off after one hour, which gave Duval the idea to profit from the tragedy. He went on a crime spree, turning guards to stone while he robbed banks, and jewelry stores. Eventually, finding this too easy he set his sights on immortality, specifically Thor’s. Thus he is in New York to do battle with the Thunder God.
Thor hears the news report of the airline passengers turned to stone and locates a similarly afflicted cab driver; he asks the police for permission to take the petrified cabbie to Don Blake’s office. As Don he examines the patient and discovers the condition is only temporary. Elsewhere, Duval has donned a creepy costume and named himself the Grey Gargoyle. Having seen Thor go to Don’s office with the cabbie, the villain heads there and intimidates our hero with a demonstration of his powers, turning a paper airplane into granite. Don dashes from the room up to the roof where he transforms into Thor. The Gargoyle follows him and the two battle, with the villain desiring to capture the Uru hammer. Thor throws his enemy off the roof but the drop to the ground does not injure the stone villain. The Gargoyle races to a gas station ("Marvel Oil!") where he creates a spark that touches off an explosion which hurls Thor to the ground. The Gargoyle tries to lift the hammer but cannot; Thor snatches it back but comes close enough to the villain for the Gargoyle to turn him to stone. The police, armed with flamethrowers (!), pursue the Gargoyle from the scene. The petrified Thor topples over, and the hammer hitting the ground turns him back into a normal Don Blake. Determining he can’t appear as Thor for the twenty-four hours until the spell allegedly wears off (can’t follow his thinking here), Don comes up with a plan to defeat the Grey Gargoyle on his own. He borrows a holographic movie projector from Tony Stark and uses it to project a lifelike image of Thor moving about the city, while Don "follows" on a motorcycle. The Gargoyle pursues "Thor" but can’t lay hold of him; he guesses the motorcyclist has something to do with the mystery. Grey Gargoyle hijacks a van and pursues Don who drives off a pier. The villain plunges into the ocean and sinks to the bottom, his weight making it impossible for him to swim. As Thor he returns to the office to praise Don’s bravery before Jane.