In Amazing Spider-Man #388, Spider-Man discovered that his parents were actually synthetic beings sent by the Chameleon to find his secret identity. Spider-Man stopped them before they were able, but what if Spider-Man's parents had suceeded? What if they had destroyed his family?
Peter Parker is asking Aunt May if she would be willing to see a doctor when Mary and Richard Parker arrive. May cries out that they can't be the Parkers, and when Peter's Spider-Sense goes off, he decides to go for a walk with May. As the pair go to Peter's apartment, Richard Parker decides they must report in. When he does so, he's ordered to kill Spider-Man. Unfortunately, Richard and Mary know that Spider-Man and Peter Parker are one and the same, and so it's off to Peter's apartment to follow orders.
Mary and Richard transform, and when they arrive, they quickly reveal Peter's secret to Aunt May, but before she can digest the information, she and Mary Jane are killed by Mary Parker. This enrages Peter, who quickly takes the offensive against his "parents". The fight moves outside, and Mary and Richard decide they must remorph into human forms and destroy Spider-Man another way. They go to the police station and tell them that Aunt May had found out Peter Parker was Spider-Man, and so he killed her and Mary Jane, and now he's after Mary and Richard.
The story quickly spreads, but Flash Thompson and Robbie Robertson believe something is rotten. Jonah Jameson, however, is set to believe that Spider-Man would do such a thing, especially when the web-slinger smashes into the Bugle and demands to know where his parents are being kept. After he learns that the location is the Avengers Mansion, Spider-Man exits the Bugle and is confronted by Captain America and the Human Torch. However, after escaping them, he swings off not to the Avengers Mansion, but the headquarters of the Chameleon.
At the Chameleon's headquarters, Spider-Man learns the truth about his "parents", and accidentally kills the Chameleon. Then it's off to the Avengers Mansion to deal with the two robotic monstrosities that have made his life a living hell. Luckily, he sees them escaping through the roof of the Mansion, and sets off after them. He confronts them and the trio begin a violent battle, which is witnessed by the Human Torch. After a violent battle, the trio tumble off the roof and Richard and Mary are impaled. Then, as Spider-Man regains his composure, he sees the Avengers, Fantastic Four, various other superheroes, the NYPD, and various other individuals standing in front of them. Though Spider-Man knows he could probably prove himself innocent, he simply gives up.