"Avengers 4" spoilers reveal Tony Stark and Scott Lang have time travel plans using the Quantum Realm. A Reddit post revealed a possible leaked description of the sequel's first trailer and it featured Tony's plan to save the whole universe from the effects of the Infinity Stones. Cast member Karen Gillan also teased how her character, Nebula, will kill her adopted father, Thanos, in the Marvel Cinematic Universe.

The fourth film is said to take place five years after "Infinity War," as the surviving heroes must band together, once again, in a last-ditch effort to stop Thanos and save their fallen comrades.

Leaked trailer synopsis

According to the Daily Express, the leaked trailer description starts with the shot of Thanos's damaged Infinity Gauntlet as he settles on an unknown planet featured at the end of the previous film. The Quinjet lands on Wakanda, as Steve Rogers and the rest of the heroes, meet Tony Stark and Nebula. Steve is relieved that his friend is safe as Tony smirks in approval.

The next scene could reveal Loki during the Battle of New York in the first "Avengers" films, as he looks shocked and baffled at the damage he created as a flash of blue light appears.

M'Baku temporarily sits on the throne of Wakanda, as Shuri and Bruce Banner are working on a secret project. Natasha Romanoff (Black Widow) visits Clint Barton's house, only to see wreckage and a map with a list of targets. Clint adopts a new costume and has named himself Ronin.

Thor and Valkyrie go to a Kree Ship seeking help, and is hinted to be Captain Marvel. Tony and Bruce now run S.H.I.EL.D., as they prepare for Thanos. Tony meets Scott Lang, and together, they use the Quantum Realm to travel back to New York in 2012, during the Chitauri invasion. Thanos noticed that one of the Infinity Stones vanished and deduces that Tony is up to something. He then dons his armor and gleefully smiles for coming carnage.

The trailer ends with films title, stating it is called "Avengers: Annihilation," and the end scenes see Hulk training non-stop, as he told Steve and Natasha that he is getting ready for his rematch with Thanos.

Nebula kills Thanos

According to Screen Rant, cast member Karen Gillan teased fans at the ACE Comic Con event at Chicago about how Nebula will kill her adopted father in the MCU. She stated that Nebula may use the Infinity Gauntlet and strangles Thanos by the throat and says "Bye Daddy." Nebula has been a huge part of Thanos's life in the MCU, as she was trained to be his assassin, alongside her sister Gamora. Her hatred for he father grew intensely after he killed Gamora for the Soul Stone. "Avengers 4" will premiere in cinemas on May 3, 2019.