精霊の守り人 - この世と平行して存在する目に見えない世界の「水の精霊」の卵を産みつけられてしまったため、父帝から命をねらわれることになった新ヨゴ皇国第二皇子チャグム。
彼は刺客の罠にかかったところをバルサという短槍使いの用心棒の女性に救われる。師匠の罪をあがなうため人助けの旅を続けていたバルサは、チャグムの護衛を引き受ける。
バルサの仲間たちとの交流の中で、皇子という生い立ちとは関係なく一人の少年としてたくましく成長していくチャグム。
バルサは刺客を防ぎながら、「水の精霊」の卵を孵しチャグムの身を守りきれるのか…。
そして、「夏至祭」や「水の精霊」をはじめとする、この世界の謎とは…。
Seirei no Moribito (Moribito - Guardian of the Spirit) - On the precipice of a cataclysmic drought, the Star Readers of the Shin Yogo Empire must devise a plan to avoid widespread famine. It is written in ancient myths that the first emperor, along with eight warriors, slew a water demon to avoid a great drought and save the land that was to become Shin Yogo. If a water demon was to appear once more, its death could bring salvation. However, the water demon manifests itself within the body of the emperor's son, Prince Chagum—by the emperor's order, Chagum is to be sacrificed to save the empire.
Meanwhile, a mysterious spear-wielding mercenary named Balsa arrives in Shin Yogo on business. After saving Chagum from a thinly veiled assassination attempt, she is tasked by Chagum's mother to protect him from the emperor and his hunters. Bound by a sacred vow she once made, Balsa accepts.
Seirei no Moribito follows Balsa as she embarks on her journey to protect Chagum, exploring the beauty of life, nature, family, and the bonds that form between strangers.
