Oguna, the youngest prince of Yamato, is dispatched by his father to assassinate Takeru Kawakami, leader of the rival Kumaso tribe. While in Kumaso territory, a stray arrow shot by Kajika, a local woman hunting game, accidentally wounds him. She aids his recovery by bringing him to her village for treatment.

During his recuperation, Oguna delves into Kumaso traditions and legends, particularly those of the Phoenix, an immortal bird revered as the tribe's eternal protector. He simultaneously develops a deep romantic bond with Kajika. This relationship becomes fraught when he discovers Kajika is the younger sister of his target, Takeru Kawakami.

Confronted with the irreconcilable conflict between his duty to Yamato and his love for Kajika, Oguna seeks the Phoenix's guidance. His struggle forces a choice: betray his father's command or kill Kajika's brother, an act certain to devastate her. The narrative explores Oguna's turmoil as he weighs familial loyalty against personal devotion, set against the legendary Yamato Takeru myth from Japan's Kofun period.

It depicts his journey from a prince defined by royal obligation to an individual torn between the consequences of love and duty, culminating in a pivotal decision that determines his path.