Melfiera, a count's daughter, faced malicious rumors about her hobby for three years, causing her to withdraw from engagement. Her future stepmother warned her that if she didn't secure a fiance in a year, she'd be sent to a convent. Fearing her fate, Melfiera attended an autumn party where she was confronted by a demonic beast, left alone. Fortunately, the "Mad Duke" of Galbraith, adorned with blood, saved her. The Duke admired her courage and love for exploring the demon world. Despite rumors, they fell in love and got engaged. But their future was threatened when Melfiera learned of her fiance's betrayal. Can they overcome this obstacle and find happiness together? A fantasy romance following two outcasts, their adoration for demon hunting, and the strength of true love.