Captain America 4 Finally Remembers The MCU's Biggest Forgotten Storyline

The early Marvel Cinematic Universe was franchise-making at its finest. It set the standard and the formula for building a cinematic universe that every studio is now following — for better and worse. The promise of characters crossing over from one movie to the next, of plot threads being planted in one movie only to be picked up in another, and large overarching stories that take years to tell was exciting and new. 

With time, however, these features have started to become bugs. The number of movies in the MCU is now overwhelming, and watching all of them to catch up before a new title feels like a chore — especially when you take the TV shows into account. 

With so many movies to watch, newer titles are now ignoring the events of past movies in order to be newcomer friendly and not lose potential audience members. This means that what was once the best thing about the MCU is mostly gone. In addition to teases for future movies that are never resolved, we now get a bunch of seemingly important plot developments that are immediately ignored by the larger franchise.

We saw this most recently in "Secret Invasion," where the entire plot of Skrulls infiltrating the planet ended up amounting to very little, and the Skrulls being kicked off Earth only barely referenced in "The Marvels." It is not all bad news, however, because one of the biggest abandoned plots of the MCU ever is finally being somewhat addressed in "Captain America: Brave New World." That's right, we're bringing back Tiamut the Celestial.

In the new "Captain America: Brave New World" trailer we see what looks like a return to the political thriller tone of "Captain America: The Winter Soldier," with Sam Wilson struggling with the idea of being used as a puppet for the U.S. government, and talk of interventionism.

While the trailer does show Harrison Ford as Thaddeus Ross, and even a brief look at the Red Hulk, the biggest highlight might be the brief shot of Wilson flying over what seems to be a mountain — which keen-eyed fans can see is actually the giant remains of Tiamut, the Celestial that popped out of the ocean in "Eternals."

The big surprise in "Eternals" was the reveal that each planet that the Eternals are sent to is meant to be a harvesting site, wherein the planet's inhabitants are used as fuel to create a new Celestial. Earth was meant to be destroyed so Tiamut could be born, but the Eternals decided not to go through with it and stopped the process, killing Tiamut — but not before a big chunk of its head and fingers popped out of the Indian Ocean and were left there for all to see.

It's not like Tiamut is the only major, world-shattering event that the MCU has conveniently left behind with barely a joke or mention. Take the Blip, the big event that the entire Infinity Saga was building up to, where half of all living beings in the universe were killed off (even if it was temporary). Though "Spider-Man: Far From Home" made the Blip a huge part of the plot, the franchise as a whole quickly pushed it aside and kind of forgot about it, save for an occasional cheeky nod.

Small events or characters are more likely to get callbacks in the MCU, like "Endgame" referencing Tony Stark's love of cheeseburgers but big, world-changing events would bet ignored. Take the Sokovia Accords in "Captain America: Civil War," which went virtually unacknowledged until a blink-and-you'll-miss-it news reel gag in "She-Hulk."

Sure, it will be cool for "Captain America: Brave New World" to finally bring back Tiamut, but don't be surprised if it ends up being little more than a brief background shot and not much else.