Clad in a blood-soaked coat and with no destination in mind, a young boy named Reto wanders into an Ainu village amidst a blizzard, whose residents provide him with much-needed shelter. All he has are two things: the memory of his mother dying before his eyes, and an ancient hunting knife without a blade...

Sylph Biebel, the duke's daughter, has just suffered a sinister plot by a friend resulting in her engagement to the prince being called off and her own banishment! But she's not just sent anywhere—she gets exiled to a kingdom where an infamous monster resides. Will her quick wit win this king's favor as she begins a new life as a librarian in a mysterious land?

Hidden within the rural countryside lies the mysterious treasure of the ancient Ainu people. A few people know of it and hold the keys to unlocking it, but only Kotan, a child of Ainu descent, is the chosen one who can locate and inherit the treasure. When Kotan suddenly befriends a man-eating tiger named Dan, the unexpected pair find themselves tangled up in the most epic and dangerous treasure hunt of their lives. Their strength is tested as they battle criminals, murderers, and other unsavory characters who seek the treasure for themselves—but their friendship is tested when a crow warns Dan that Kotan will be the one to end his life. Can brave Dan and his best friend Kotan survive the trials that await them?