When an unknown family targets Tsuna Hibari takes initiative and swears to protect this small herbivore if only to protect Namimori itself. As time passes Hibari realizes he wants to protect Tsuna for more than one reason. Especially with the enemy continuing to hide in the shadows waiting to strike again. But tragedy ensues as war erupts in the mafia world.

Prince Hibari was turned into a beast that one winter night, and the only way to return to normal is to love and be loved in return. When Tsuna becomes Hibari's prisoner in place of his father, he can only see him as a beast and nothing else. Can Hibari gain this herbivore's trust and love and break the spell while a certain pineapple's scheming on how to make Tsuna his?