Solomon Grundy's origin is re-told and he is imprisoned in an energy bubble by G.L., but shattered y lightning. His only thought is to find G.L. and kill him. Meanwhile, at JSA HQ, the Lantern stands alone and hears a knock on the door, opens it and explains, "You!" Much later, the other JSA members arrive and discover the HQ ripped apart, with a large muddy footprint on the floor. Johnny turns on the radio, which reports Solomon Grundy is on the loose, seen at various towns. The JSA puts the pieces together, and, leaving Wonder Woman behind to gather news, the rest leave to find Grundy.; While Hawkman briefly visits Harford and discovers Grundy is heading toward Regis, the editor of Regis' newspaper is fuming with his Dad over how he runs the Herald. His father doesn't condone his son's scandal sheet, but as they argue, Grundy smashes his way in, looking for G.L., and, as he tears the place apart, Hawkman arrives. Announcing he is a friend of G.L., Grundy vows to kill the Hawk as well. Aftr knocking Hawkman out, Grundy storms away. When the Feathered Fury revives, father and son make peace, vowing to unite their papers and work together, and Hawk leaves to locate Grundy.; When Jimmy leaves the house to play marbles with his friends, the maid signals to her co-hort to enter the mansion so they can rob the safe while the parents are away. While they do this, Jimmy and his friends encounter Grundy, who tries to play marbles, but crushes them....and the kids scatter. Mid-Nite gets a tip on Grundy's location and follows footprints to the mansion and catch the crooks in action, and mops them up as Grundy enters. In danger, Mid-Nite hurls a blackout bomb, which dis-orients Grundy, who then storms out. Mid-nite leaves Jimmy to call Police, then trails Grundy again.; Three thugs in Zenith get Grundy to break into a business for them, while Johnny is being mid-led to Grundy's true location by girls in cahoots with the thugs. But Johnny remembers where he is to go and arrives in Zenith as Grundy and thugs walk out he door. Grundy knocks Johnny out and then leaves. When Johnny awakes, the girls lead him to a cereal factory, and he attacks a phony Grundy and thugs walking out the door. Johnny attacks, knocks Grundy down and pulls his legs (actually stilts) off. The Thunderbolt appears, knocks out the thugs, and offers to help Johnny find the true Grundy.; The city of Moosehead is aiming to replaced 45-year veteran Police Chief McGurk with a younger man, Spenser Blade. When Solomon Grundy arrives in town causing mayhem, both Spenser and McGurk take on Grundy with a gun, which proves ineffectual. Spenser runs for his life, leaving the town at Grundy's mercy. The Flash arrives from Alcona, sees damage and notes McGurk taking on Grundy. Flash battles Grundy rather unsuccessfully, then leads the monster out of town, where Grundy knocks Flash off a cliff. He grabs a branch sticking out, then scrambles up and pursues Grundy again.; In Lambert City, Baldy Balsom convinces his thug buddies that he not washed up and he'll commit any crime he wants without anyone stopping him. They believe it when Grundy walks in the door, and he agrees to help Baldy if he will tell him how to find Green Lantern. While Grundy is committing three crimes, the Atom gains a clue to the monster's location, and arrives at a shoe factory and stops Baldy and his men. Then Grundy knocks the Atom unconscious, senses he will get no information from Baldy, and leaves. Atom takes the crooks to jail, the sets out after the Marshland Monster again.; The scene shifts back to the moment at JSA HQ where Green Lantern had opened the door in response to a knock, and said, "You!" To his surprise, Doiby Dickles walks in, and informs G.L. that Grundy has freed himself and is on the loose. G.L. and Doiby smash out the window to track down Grundy and Grundy arrives there soon after, tearing the place up. The Lantern then uses a modified radio attuned to track down Grundy, and locates him in State Park. As the two battle, G.L. is dazed and goes over a waterfall, where Grundy holds his head underwater, hoping to drown him.; The JSA arrive in time to rescue Green Lantern and battle the Marshland Monster, eventually, by sheer numbers, holding him down in water. As darkness sets in, Johnny looks at the Moon, musing what "the man in the Moon" would do with Grundy. So, Green Lantern puts Grundy back into a green bubble formed by his ring and personally transports Grundy to the Moon's surface. Later, as the members look up at the glowing orb in the sky, they wonder if even the Moon can hold Grundy?