Over the past few days, the internet has been rife with trailer leaks full of spoilers.

It's rumoured that Marvel Studios is planning to release four Avengers Doomsday teasers over the next month.

However, two have already appeared on X, with the first revealing the return of Chris Evans' Captain America as a young man in the 1940s, with a surprise newborn baby.

Meanwhile, the second MCU trailer (also yet to be released) features Chris Hemsworth's Thor, who had a daughter in Thor Love and Thunder.

Fans will also remember that Robert Downey Jr's Doctor Doom was spotted kidnapping the child Franklin Richards at the end of The Fantastic Four: First Steps from Earth-828.

Now, a reliable Marvel leaker has revealed some alleged major Avengers Doomsday plot spoilers, and the last is a shocking Avengers Endgame twist.

Main Middle Man wrote on X: "The teasers for Steve Rogers and Thor will focus on their relationship as fathers now that they have children. Basically, they will repeat the same plot as Stark messing up an entire universe just so his daughter can exist safe and sound. So creative... In Doomsday, they will ctrl+c ctrl+v Scarlet Witch's plot in the story of Steve, Thor, and Doom. They will do anything to protect and avenge their children... [Doom] lost his son, which is why he is interested in Franklin (aside from his powers)."

But then came the absolute shocker.

The scooper added: "Steve Rogers did not return the stones, which is why he is an essential part of Doomsday."

Fans will remember in Endgame that after borrowing the Infinity Stones from the past for the Stark Gauntlet, Steve was tasked with returning them. However, he went back to the 1940s to marry Peggy Carter and aged naturally.

Since then fans had hoped that Marvel would make a miniseries depicting Cap's returning mission. But now it seems the plot twist is that, for whatever reason, he didn't. And as the Ancient One warned Smart Hulk, there would be dire consequences for the Marvel multiverse if that was the case.

Our best bet is that it meant Doom's son never existed. No doubt Loki, now enthroned as God of Stories, will be getting involved as the one who holds all timelines together.