如月龙司(下野纮 配音)只是一介普通高中生,没想到表姐七尾英理子(野上尤加奈 配音)从国外带回来的一个神秘木箱彻底颠覆了他平凡的命运。在木箱中的,躺着一个叫萝丝(钉宫理惠 配音)的金发少女。少女对龙司一见钟情,而面对少女火热和直接的表白,龙司只是感到十分的困扰。就这样,龙司和萝丝的“幸福”生活开始了。 萝丝的真实身份为龙之少女,她的失踪在黑道上引起了轩然大波。为了夺回萝丝,黑道派出了邪恶的黑暗组织。在波折中,龙司逐渐发现了自己对萝丝的真正心意,为了保护自己所爱的人,他决定拿出勇气和力量,于黑恶势力决一死战。A normal high school boy Ryuji Kisaragi's peaceful life is turned into an adventure by the return of his second cousin, Eriko. Ryuji and Eriko seize a relic box from a black broker named FANG. In the box, they find a red dragon girl whom Ryuji names Rose because of her rose like pattern on her left hand. In order to protect Rose from the black organization, Ryuji decides to fight using his power as a relic handler.