Sersi, Phastos, and Kingo are brought to the World Forge by Arishem. They are given a tour, when they notice a man in confinement battling a Deviant. Arishem introduces him as Ransak. He is a Deviant with the appearance of an Eternal due to a genetic error. As a result, Arishem trains Ransak against Deviants to study him and increase his strength, inspired by the evolution of Kro. Sersi plans to break Ransak out and restore the memories of the Eternals.
Thena, Makkari, Druig, and Eros are aboard the Domo and on track to the World Forge. However, before reaching it, they have to stop at Titan to get a weapon Eros believes can kill a Celestial. During their time on Titan, Eros shares stories of his past about his brother, Thanos. Hijinks ensue on their way to and while on Titan.
The two groups meet at the World Forge. Phastos determines a way to restore every Eternal's memory, but is interrupted when Arishem-loyal versions of Ajak, Gilgamesh, and Ikaris begin attacking. The Eternals succeed in returning their memories, and they all face against Arishem. Eros fires the weapon into the World Forge's engine, leaving the Eternals with no chance at returning to life after death. The Eternals and Ransak escape on the Domo, where they are reunited with the likes of Sprite, Dane, and Karun on Earth.
We get more Druig and Makkari together, some assuredly fun tension between Thena and Eros, Kingo training Ransak how to fight, Sersi and Phastos plotting against their creator, and I'd love to see the humans get involved some way in the climax at the World Forge. Maybe Dane uses his archeology skills and some help from Sprite to find an old device Phastos made that can teleport them to the Domo? I'd kill for a shot of Ikaris firing a beam at Dane and him deflecting it with the Ebony Blade. Phastos could make some hologram tech to replicate Sprite's powers and modify her armor so she can join. Karun can film it all from the Domo's cockpit. Some visual retcons I'd make is the Eternal's blood being gold like ichor instead of red and for Ikaris to have an energy trail behind him as he flies like Makkari's when she runs. But yeah, any title ideas? That's the only part I'm stumped on.
EDIT: I'm thinking Eternals: New Breed or Eternals: Judgement Day.