Peter's long lost parents have returned, though in time we would find out they were not what they seemed. Harry Osborn was imprisoned after his last fight with Spider-Man, even though he threatened to reveal Peter's secret if he turned him to the authorities. In the last issue, Peter returned home only to find Harry, Liz and Normie there. Due to lack of evidence, Harry had been released from the Vault. He sent Mark Raxton (the Molten Man), his brother-in-law, to a new job in California, probably so he couldn't interfere. He was burning in fever, but he wanted to say hello to his best friend.
After they leave Peter argues with MJ: he wants her to leave to Florida with Aunt May, she refuses and storms off. Peter pays a visit to Harry only to find out he's not home, something MJ also realises when the Green Goblin picks her up from the street and flies away.
All the while with little Normie massacring a Spider-Man doll. The kid's got serious issues.
Knowing Harry isn't home, Peter leaves and swings around the city to find him, while Normie keeps punishing the doll.
Menwhile, the Goblin takes MJ to the Brooklyn Bridge. He tells her he's not going to hurt her. He claims Peter set up Norman when Gwen Stacy died. Harry shows serious disturbances, as the simple mention of his father ticks him off. He promises never to hurt MJ and Aunt May, no matter what. She asks him to take her home.
A visibly upset Spidey catches a couple of kids who broke into a house, and treats them a bit more severely than he should. He comes home to check if MJ's there, and he finds her with an unmasked Goblin. Rage speaks louder than sense, and he attacks Harry. Harry doesn't react, and MJ tells Peter to stop, that Harry didn't want to harm her, just talk with her. Harry once again promises that MJ has nothing to fear from him, and goes home. Peter and MJ argue on what to do, and hug each other. At home, Harry's unstable personality scares Liz.
A few days later, things have cooled off with Harry in bed due to his fever. Peter walks around wondering what to do, when the Goblin hovers by. He teases Peter and leaves. Then he pays a visit to the Bugle, where he explains to a terrified Jameson about his plans to create the Norman Osborn Foundation, an institution that'll use his family fortune in charity works. Peter comes in, and Harry teases some more, promising that the foundation will recover Norman Osborn's image when it opens in 6 weeks. Then he promises some exclusive information about Spider-Man to Jameson and leaves.
A few weeks later, Harry keeps teasing Peter, and tells him he's going to ruin his life and kill him when he least expects it. Meanwhile, he has great plans for the city, and if Peter tries to stop them he'll destroy his life.
At the Foundation, everything is almost ready, in time for the big opening. Liz feels proud, but Harry almost faints. He tells her he must keep working, for them and for his father. At night, alone at the Foundation while Normie sleeps, Harry speaks to his father's painting. He tells him that he would be proud, that he's driving Peter insane. Also, in a couple of weeks, he's going to inaugurate the Foundation, and many of Norman's best friend will be there. All the snobs who thought that they were superior to the Osborns will die when he detonates the building. Visibly insane, he vows not to commit the same mistake as his father, not to forget his family.
Meanwhile, MJ tries to open Liz's eyes, but to no avail, and Spidey tries to find out what are Harry's plans. MJ then goes to the foundation, where she tries to talk Harry out of his insanity. He almost breaks, but eventually tells her the only way to settle things is with power. Then a security camera shows that Spider-Man has arrived, and Harry tells MJ that it's no use to ask him to stop: Peter doesn't let him stop!
Harry dresses the Goblin costume and meets Spider-Man at the roof for their final fight, in a beautiful battle sequence illustrated by Sal Buscema. It ends with both of them crashing down inside the building, and Harry managing to sting Peter with a drugged needle. Peter falls, and Harry tells him not to worry, that he won't let him die alone, and activates the two-minute timer for the explosives. He says people like them shouldn't live, that they destroy everyone around them. Then he remembers MJ and Normie are in the building. Peter can't move, so he tells Harry to save them. Harry says he can't, he isn't a hero, and that his father used to say, we don't know what his father used to say, because Peter interrupts him to say he doesn't care about his father, he cares about him, and he's the only hero they've got. Harry glides back to MJ and Normie and takes them out of the building. When he mentions a bomb, MJ (who's holding little Normie on her lap) asks him if he let Peter inside to die. That snaps Harry's mind, and makes him become lucid. He glides inside, picks up Peter and leaves just as the building explodes. Outside, Harry collapses due to his illness. He tells Peter that he did what he would have done, like a real hero. Peter asks him why did he came back for him, and Harry says, "Because you're my best friend."
Later, in the ambulance, Harry isn't doing well. With a tighter grip on Peter's hand, he smiles and passes away. He's DOA at the hospital. When MJ arrives, no words are needed. Spidey holds her, and she cries. She leaves with Normie, while Spidey stays alone grieving in the parking lot.