In a quiet corner of modern Japan, there exists an ordinary pet shop, Shinobu Breeders, where customers come searching for cute and loyal companions. However, behind its innocent façade lies a covert training facility for "Ninken"—Ninja Dogs, the ultimate partners of modern-day shinobi. What supernatural abilities do these specially trained assassin hounds possess?What deadly missions await them in the shadows of contemporary society? As the silent war of the ninja world rages on, the true power of the "Ninken" is about to be unleashed! A high-speed, action-packed ninja thriller begins!