The first episode of "Tales of Wedding Rings" begins with the encounter of the young Satou Haruto with the girl Nokana Hime and an old man under a golden pillar of light in the forest. Hime, who introduces herself to Satou, wears two rings around her neck, one for herself and one for her future husband. She makes a pact with Satou to be friends if he keeps her secret.

Ten years later, Satou and Hime, who have been close friends since childhood, attend high school. Satou's feelings for Hime have deepened, and his friends encourage him to confess his love to her before it's too late. The opportunity seems to arise when Hime invites Satou to a summer festival. However, during the festival, Hime announces that she will be leaving.

Desperate at this news, Satou follows a golden pillar of light into the forest, where he finds Hime about to step through a portal to another world. She explains to him that she will return to her world to get married. As Hime steps through the portal, Satou jumps after her, driven by the desire to protect her.

Satou finds himself in a church at the wedding ceremony of Hime, whose real name is Krystal Novaty Nokanakita, and Prince Marmarugias Gisaras. The ceremony is abruptly interrupted by a monster attack. Hime's grandfather urges her to give the Ring of Light to her prince, but instead, Hime rushes to Satou and kisses him. This fills Satou with power, allowing him to defeat the monster with a sword.

When Satou regains consciousness, he finds himself in a wedding room with Hime, who informs him that they are now married. Hime has chosen Satou over the prince, which could have political consequences. The couple is officially introduced to the people, who are thrilled by their hero and Ring King from another world.

The episode ends with another attack by the monsters from the abyss.