Some time ago, Midtown High
After the battle of the Mysterios at Midtown High, a janitor is left to clean up the mess. Principal Harrington is still hiding out in the closet after Spider-Man told him to stay in there. Rather than simply let him out, the janitor kills him.
Spider-Man, Sandman, and Dennis drive to the location that the helmut of the Spider-Man from 2211 is telling them they can find the man that appears to be Ben Parker. They comment that all they need is a talking great dane. Spidey says then he'll be Fred and Dennis calls dibs on Shaggy. Sandman is upset because he doesn't want to be "one of the broads." Spidey tells him he can be Scrappy. Sandman thinks that sounds good until he finds out it's "the obnoxious sawed-off puppy."
Meanwhile, Sandman's father, Floyd Baker, is told that his death sentence has been moved up to this night. Because both Sandman and Spider-Man tried to help him escape, the judge gave a special order to have him face the chair that night.
Flash and Betty drive home after their disastrous dinner date. Flash seems reluctant to believe Betty when she suggests that perhaps Miss Arrow, the school nurse, doesn't want them together. Just then, she sees Arrow standing outside. When Betty tries to get Flash to see her, they rear-end a parked police car. Arrow is gone but spiders are seen crawling into the sewer.
The helmut takes the gang to Midtown High. Spider-Man is surprised by this. Inside, the helmut tells him that there are eleven thousand lifeforms inside. They find Principal Harrington with a shotgun. Sandman attacks him right away demanding to know what he has to do with the dead guy in the alley (that his father was accused of killing). Spider-Man tries to stop him and also figure out where all the lifeforms are. He sees some spiders crawl into an air vent.
Principal Harrington has changed into Sandman and attacks him. As they're off guard, he changes into the Spider-Man from the year 2211. He grabs the helmut and throws it out the window, where it lands by Dennis' van.
Spider-Man figures out that since there was a Spider-Man and a Hobgoblin in the year 2211, this must be the Chameleon from the same year. It turns out he came with the Hobgoblin from 2211. It turns out that he was in the alley way when the Ben Parker from another dimension stumbled across him. The Chameleon shot him and after taking his DNA through his blood, was able to take his appearance. That's when Floyd Baker came across him and was accused of killing him.
Then the Chameleon transforms into a huge creature. Dennis comes in with the helmut. Throwing it to Spider-Man, Spidey places it on Chameleon's head and instructs the helmut to adminsiter justice (Spidey had specified "poetic justice" in the van).
As Floyd Baker sits in the electric chair, his body is switched with that of the Chameleon's. Sandman is reunited with his fater.