Ryuuou Heika no Gekirin-sama

Princess Ruiying of the Rat Clan, the weakest of the thirteen animal clans, was summoned to the palace of the Dragon Clan, as the Dragon King sought a bride. But instead of competing with the other princesses, her goal is to check out the dragon palace's library, the largest in the world. Seven days after arriving, Ruying was reading alone in the library when she was caught by a handsome man of the Dragon Clan. He suddenly kisses her and says, "I've finally found you," and her future is about to change forever.