"Fate/Grand Order -Absolute Demonic Front: Babylonia-" is a 21-episode anime adaptation of the seventh chapter of the mobile game "Fate/Grand Order." The story is set in ancient Mesopotamia during the Age of Gods, where humanity faces extinction due to the collapse of human history. The protagonist, Ritsuka Fujimaru, a Master of Chaldea, and their Servant, Mash Kyrielight, are dispatched to the Singularity of Babylonia to correct the timeline and prevent the incineration of humanity.

The Singularity of Babylonia is a distorted version of 2655 B.C., where the goddess Tiamat, the primordial mother of life, threatens to destroy humanity. Ritsuka and Mash ally with the Caster-class Servant, Gilgamesh, the king of Uruk, who is actively defending his city against the onslaught of demonic beasts. The story unfolds as they gather allies, including other Servants such as Enkidu, Ishtar, and Quetzalcoatl, to confront the growing threat posed by Tiamat and her forces.

The narrative explores themes of survival, sacrifice, and the resilience of humanity. Key events include the defense of Uruk against relentless attacks, the discovery of Tiamat's true nature as a Beast-class entity, and the eventual confrontation with her in the underworld. The characters face moral dilemmas and personal challenges, with Gilgamesh's leadership and Ritsuka's determination playing pivotal roles in uniting the disparate forces against the existential threat.

The anime balances action, character development, and world-building, staying faithful to the source material while expanding on the lore of the "Fate" universe. It concludes with a climactic battle against Tiamat, where the combined efforts of the protagonists and their allies ultimately save humanity from extinction, restoring the timeline and ensuring the continuation of human history.