Shadow Star Narutaru

A summer vacation at her grandparents' house brings Shiina Tamai incredible adventures. While walking along the seashore, the cheerful young schoolgirl comes across a mysterious creature that instantly catches her attention. It is something entirely unique among all the other inhabitants of the sea, and Shiina feels a special bond with it. She even gives the creature a name: Hoshimaru. The time spent with Hoshimaru fills her days with joy and wonder, and the two talk, play and explore the world around them like old friends. But when the time comes to say goodbye and go home, her heart aches at the thought of parting with her new friend.

Back in the reality of school life, she learns that Hoshimaru is just one of many similar creatures. Other children have also found strange companions of their own. Some of these creatures and their masters are kind and friendly, but not all of them. Some turn out to be hidden enemies whose intentions are far from friendship and understanding. Shiina is faced with the challenge of telling friend from foe in this strange world, which she stumbled upon by chance during her summer vacation, and which proves to be far darker and more dangerous than she could have imagined.