When her mother's illness takes a turn for the worse, Lilitia meets her father, the Marquis Castion. With no one else to turn to, she agrees to join the House of Castion and become their political tool in exchange for her mother's medical treatment. But as if relinquishing her freedom weren't enough, the duke's son and her new fiance Jacob absolutely detests commoners. Years later, Lilitia continues to suffer his torment. Under Jacob's instructions, she must now act the bully towards the baron's daughter at the academy, all to deter suspicion away from their secret relationship, One evening, as Lilitia recovers from her torturous day, a strange, handsome man bursts into her home. Enter Ultio, the thief causing a stir in the kingdom for delivering justice to its corrupt aristocrats. Before he makes his escape, the kind-hearted Lilitia notices his injury and offers to mend his wound. What she didn't expect, was how he proposes to return the favor: Help her end her doomed engagement to Jacob! With the mysterious gentleman thief's aid, perhaps freedom (and romance) for our "villainess" in distress is just around the corner!
庶子として侯爵家に引き取られたリリティアは、病気の母の治療と引き換えに父である当主に侯爵家繁栄の手駒にさせられ、自由を奪われていた。
傲慢な婚約者からは浮気相手である男爵令嬢との仲を邪推されないよう”悪役令嬢を演じろ”と命じられ、学園でも居場所がない。
そんな地獄のような日々を過ごしていたある日、リリティアは世間を騒がせている怪盗・ウルティオに出会う。
怪我をしていた彼を助けたことで、リリティアの人生が大きく動きだし―…？
「お嬢さん 俺と婚約破棄を目指さないか？」
悪役にされた薄幸令嬢が正体不明の真摯な怪盗と婚約破棄を目指すシンデレララブストーリー！