On Earth-982, the Age of Heroes (the boom of superhero activity generally marked by the first appearance of the Fantastic Four) happened about 15 years earlier than on Earth-616. Pragmatically speaking, this means that most of the events, history, and character history associated with the heroes of Earth-616 happened 15 years before they would have on Earth-616, but the overall political, technological, and sociological progress of the world is exactly concurrent with Earth-616. As such, a lot of the superheroes of the past have either grown up, grown old, or retired, and now new groups and new superheroes are proving themselves in protecting the world.
By this time Spider-Man has retired, having lost his right leg in the final battle with Norman Osborn following the Gathering of Five. Captain America is finally starting to feel his age slow him down, and the Fantastic Four has now become the Fantastic Five. Younger heroes like Nova have become seasoned veterans, while others such as Cassie Lang and Kristoff Vernard have risen to prominence.
While the main point of divergence from Earth-616 is early arrival of the Age of Heroes, this leads to many other smaller deviations from the main Marvel continuity. One example lies in the more catastrophic outcome of the Gathering of Five. Also, on Earth-616 Peter and Mary Jane Parker had a daughter, who they believed to be stillborn; on Earth-982, the child survived, but was kidnapped by Norman Osborn. Kaine, a clone of Peter Parker rescued her and returned her to her parents. She later grew up to become Spider-Girl.
Cain Marko (Juggernaut) and Sachi Yama also had a child, Zane Yama. Zane grew up without his father (who was still stuck in some parallel universe, probably the Ultraverse), but knew of his role as the Juggernaut. When he inherited a portion of his father's power, he decided to become the costumed crime-fighter, J2. Similarly, Wolverine and Elektra had a daughter, Rina who became Wild Thing, and Flash Thompson and Felicia Hardy (Black Cat) have a daughter, Felicity.
Features the adventures of Spider-Girl, Darkdevil, Fantastic Five, a new group of Avengers, the Buzz and others.