At the start of this issue, Spider-Man is swinging along when he passes two men who call out that they want to talk to him. Upon talking to them, he finds out that they want to to build a Spider-Mobile with a new type of engine they have invented, in order to promote it. Spider-Man dismisses the idea as stupid, and swings off. Unknown to him, a man named Frank Oliver (better known as the Kangaroo) is watching him swing off, whilst thinking about how Spider-Man beat him so badly that he hasn't gotten the nerve to go back to crime. After Spider-Man leaves, the Kangaroo is approached by the mysterious scientist Jonas Harrow, who tells him that he has a proposal to make to him.
Spider-Man then goes to Empire State University, where he
is told by Professor Warren that he has to start attending his classes more often. Peter also meets Mary Jane and Flash Thompson, but when they ask him to hang out with them, he angrily walks away, telling them he doesn't want to go. Peter then heads back home a few hours later.
At a laboratory, Jonas Harrow puts the Kangaroo to sleep with some ether, before operating on him. After many hours of work, Harrow has finished, and wakes up the Kangaroo. The Kangaroo tests his strength, and finds that Harrow has attached devices to him which augment his strength with compressed air. Harrow then starts to tell the Kangaroo what his plans for him are, but then the Kangaroo leaves, telling Harrow that he has his own plans.
Meanwhile, Spider-Man returns to the men who asked him to build a car before, since he needs money for his bills. After receiving an advance, he leaves, but is attacked by the Kangaroo, who guessed that Spider-Man would return to this area. The Kangaroo's enhanced strength gives him an advantage of Spider-Man for a few moments, but then the Kangaroo's head starts to burn up with pain, and he is forced to leave when a voice tells him to go. Spider-Man then goes to the Baxter Building to meet with the Human Torch, since he needs his help building the Spider-Mobile.
Around this time, the Kangaroo has reached the destination he was told to go to, and finds Jonas Harrow there. Harrow explains that he had a pacemaker embedded in Kangaroo's brain, so that he can make sure the Kangaroo will obey him. After telling the Kangaroo what to do, the Kangaroo leaves for a laboratory, since Harrow has ordered him to retrieve a radioactive isotope. As the Kangaroo breaks in, an alarm goes off at the Baxter Building, since it has detected the police radios reporting the Kangaroo breaking in. Spider-Man then goes off to stop the Kangaroo, telling the Human Torch that it's his enemy, so it's his responsibility.
Spider-Man reaches the lab, and starts attacking the Kangaroo. The Kangaroo mentions that he has to steal the isotopes, but Spider-Man warns him against it, since the isotopes could burn him up to nothing. The Kangaroo ignores this, and goes into the room with the isotopes, but is disintegrated to nothing, as Spider-Man predicted.
At the end of the issue, Mary Jane goes to visit Harry Osborn, but Harry refuses to let Mary Jane into his apartment. Mary Jane leaves after realizing that Harry doesn't care, whilst Harry thinks that he's now the Green Goblin after taking the costume off of his father's body.