E-Rantel, the capital city of the newly established Sorcerer Kingdom, suffers from a dire shortage of goods. Once a prosperous city known for its trade, it now faces a crisis due to its caution—or even fear—of its king, Ainz Ooal Gown. To make amends, Ainz sends Albedo to the city as a diplomatic envoy. Meanwhile, the cardinals of the Slane Theocracy discuss how to retaliate against Ainz after his attack crippled the Re-Estize Kingdom's army, plotting for the Baharuth Empire to take over the Sorcerer Kingdom. However, when Emperor Jircniv Rune Farlord El Nix arranges a meeting with the Theocracy's messengers at a colosseum, he is confronted by none other than Ainz himself. With their secret gathering now out in the open, the emperor and his guests learn that Ainz has challenged the Warrior King, the empire's greatest fighter, to a duel. With Ainz's motivations beyond his comprehension, Jircniv can do nothing but watch as humanity's future changes before his very eyes.

Despite Kyouko Honda's tragic death, her vivid memory lives on, providing guidance through times of hardship to her close ones. However, Kyouko was not always the wise and radiant person that she is fondly remembered as in the present day. Feeling deserted by her own family and rejected by society, a young Kyouko abandons stability for a life of delinquency, jeopardizing her education and future. Fortunately, her descent into despair is interrupted by a fateful encounter with her husband-to-be Katsuya, who has recently started his teaching internship at her school. With a composure surprisingly unaffected by Kyouko's tantrums, Katsuya quickly wins her over through his gentleness and attention toward her—sincere gestures that she has never received before. As the two grow closer together, Kyouko opens her tormented heart to him and, along with it, a door to new horizons.

Endou, a night guard, was patrolling the mall as usual. But this night was going to be different from usual...

The fourth season of .