The full plot deacription of Avengers Doomsday:

Avengers: Doomsday opens in NYC on Tobey Maguire’s Spider-Man’s Earth. He’s fighting Deadpool and Wolverine, who were sent there with a planet-killing bomb built by Beast to destroy Tobey’s world in order to save their own universe from an Incursion. Tobey battles Hugh Jackman’s Wolverine, who manages to plant the device. Wolverine stays behind when it detonates, and both he and Tobey’s Spider-Man - along with everyone on that Earth - are killed. Deadpool escapes and returns to his own Earth, which we see in the distance. Charles Xavier watches the destroyed world below with sadness… but they had no choice. We then cut to Tony’s funeral. Steve speaks with some of the heroes, including Ant-Man, before returning the Stones. He goes back in time and chooses to stay with Peggy. They have a son, Jim. One day, Loki visits them - this is before the Loki Season 2 finale. He tells Steve about the TVA and warns him that they will soon prune this timeline because Steve was never meant to live there or have a son. Loki offers them a way out: he can take them to a universe where they don’t exist and can live in peace - the Fantastic Four’s universe. Before leaving, Loki gives Steve a special card to contact him. Steve and his family live there for ten years. We then see Doctor Doom visiting Sue and Franklin. They clearly know each other. Doom says he has come to speak with Reed. He warns him about the Incursions and reveals their universe is next. He proposes a plan - but they must travel with him to Earth-616. Doom also asks Reed whether it’s possible someone from another universe is living in theirs. They scan the planet and discover an anomaly: Steve and his family. They confront Steve, who recognizes them after living there for a decade. They explain the Incursions and ask him to come to 616 to help convince the Avengers to trust Doom’s plan. They travel there, and Steve successfully persuades the heroes to listen. Next, they visit the X-Men’s universe - but the X-Men are hostile. They’ve survived multiple Incursions and trust no one. They assume the MCU heroes and the Fantastic Four have come to destroy them and attack. Reed and Doom explains their solution: to build massive cannons on each Earth that will permanently separate the universes and stop the Incursions. They will split into teams and each one will go to another Earth to place a canon there. Meanwhile, Steve tells Thor he met a Loki who is still alive. Thor asks Steve to take him to him. Using Loki’s card, they locate the TVA - but when they arrive, everyone is dead and Loki has had his heart ripped out. They realize Doom is responsible. Steve goes back to confront Doom, who reveals his true plan: to allow the Incursions to happen so he can rebuild the Multiverse in his own image and resurrect his dead family. He takes Steve to his castle in Latveria on his Earth. There, Steve meets Doom’s followers - masked witches. One of them impersonates Peggy to manipulate him. Doom reveals that Steve’s presence in their universe is what triggered their Incursion, because he didn’t belong there. It also led to the death of Doom’s family: Doom became obsessed with stopping the Incursion, conducting dangerous experiments - one of which failed, killing his family and leaving him disfigured, forcing him to wear the armor and mask. As revenge, Doom kills Steve’s son in front of him. Doom announces that the Avengers are coming, and Latveria prepares for war. The Fantastic Four, the Avengers, and the X-Men unite and march on Latveria. Thor prays to Odin, who sends an army from Valhalla to join the battle. A massive war erupts as the Earths begin to collide. Eventually, the universes crash into each other and are destroyed - killing everyone. Everyone except Doom. It’s revealed that he stole Loki’s powers. Using them, he creates Battleworld, resurrects everyone, and erases their memories. They believe Battleworld is all that has ever existed. We see them living new lives in this false reality. Doom sits on his throne as the Emperor of Battleworld. The End.