In a world not quite as ordinary, Isabelle Howell appears to be an ordinary girl, but there's a secret she'd like to share. She's actually a skilled Slayer, fighting against the dark forces that lurk unseen, preying on innocent lives. While most people remain oblivious to her nightly battles, she's dedicated to her mission and dreams of being part of the elite, tackling the most perilous tasks. An exciting opportunity presents itself when she receives a top-secret assignment - to take down the notorious Cassius Lockwood, a powerful pureblood vampire known for his cruelty and unyielding nature. The prospect of proving herself and climbing the ranks appeals greatly to Isabelle, but the thrill of the challenge is overshadowed by an unexpected encounter. When she confronts what she believes to be Cassius, instead of triumph, she feels a mix of confusion and unease. His words, spoken in that moment, linger in her mind long after the encounter, leaving her questioning everything she thought she knew about their encounter.