"Fate/Extra Last Encore" is a 2018 anime series based on the "Fate/Extra" video game, set in an alternate timeline within the larger "Fate" franchise. The story unfolds in a virtual reality known as the Moon Cell Automaton, a vast supercomputer that records and simulates human history. Within this digital realm, a Holy Grail War takes place, where Masters and their Servants—heroic spirits from history and myth—battle for the ultimate prize: the Holy Grail, which grants any wish.

The protagonist, Hakuno Kishinami, awakens in the Moon Cell with no memory of their identity or past. Guided by a mysterious Servant named Saber, Hakuno begins to ascend the layers of the Moon Cell, a structure resembling a massive tower, each floor representing a different stage of the Holy Grail War. The battles are fought in a turn-based format, with Masters and Servants strategizing to exploit their opponents' weaknesses. However, the Moon Cell is a decaying world, filled with remnants of past wars and distorted realities, reflecting the despair and corruption of its inhabitants.

As Hakuno progresses, they encounter other Masters and Servants, each with their own motivations and tragic backstories. Among them is Rin Tohsaka, a skilled mage who becomes an ally, and Rani VIII, a mysterious girl with ties to the Moon Cell's inner workings. The narrative explores themes of existentialism, identity, and the consequences of human ambition, as Hakuno uncovers fragments of their forgotten past and the truth behind the Moon Cell's purpose.

The series is notable for its nonlinear storytelling, blending elements of mystery and psychological drama. Flashbacks and cryptic visions gradually reveal Hakuno's connection to a previous Holy Grail War, hinting at a deeper significance to their journey. The animation style, characterized by vibrant colors and surreal landscapes, complements the otherworldly setting of the Moon Cell.

"Fate/Extra Last Encore" diverges from the source material in several ways, offering a unique interpretation of the "Fate/Extra" universe. It focuses on the aftermath of a failed Holy Grail War, emphasizing the consequences of unchecked desire and the cyclical nature of conflict. The series concludes with Hakuno confronting the Moon Cell's core, where the true nature of their existence and the Grail's purpose are revealed, culminating in a climactic battle that challenges the very fabric of reality.