"Harukanaru Toki no Naka de 3: Owari Naki Unmei" is a fantasy anime series based on the otome game of the same name. The story is set in a fictional version of Japan's Heian period, blending historical elements with supernatural themes. The protagonist, Kasuga no Misono, a high school student, is transported to an alternate world called Kyou, a land plagued by conflict and spiritual disturbances. This world is divided into eight provinces, each protected by a guardian deity, and is under threat from the Genbu, a malevolent force seeking to destroy the balance of the world.

Kasuga no Misono discovers she is the Priestess of the White Dragon, a figure destined to summon the eight dragon gods and restore peace to Kyou. Accompanied by the Hachiyou, eight warriors each linked to one of the dragon gods, she embarks on a journey to unite the provinces and confront the Genbu. The Hachiyou include characters such as Taira no Tomomori, a noble warrior with a strong sense of duty; Minamoto no Yoritomo, a pragmatic and ambitious leader; and Benkei, a loyal and protective monk. Each warrior has a unique connection to their respective dragon god, and their personal struggles and relationships with Kasuga no Misono play a significant role in the narrative.

As the story progresses, Kasuga no Misono faces numerous challenges, including political intrigue, battles against the Genbu's forces, and the emotional burden of her role as the Priestess. The series explores themes of destiny, sacrifice, and the bonds between individuals, as the characters navigate their intertwined fates. The climax involves a confrontation with the Genbu, where Kasuga no Misono must make difficult choices to fulfill her role and protect the world of Kyou. The resolution ties together the fates of the characters, emphasizing the impact of their journey on both the world and their personal lives.