Posy Pinkerton is in need of a change. In her late 20s, she’s been comfortably navigating life as a serial monogamist. She has Tom, her fiancé who works as a doctor, a promising career as a medical illustrator, and a passion for visual art. However, a chance meeting with Jack, a dashing and sophisticated businessman, begins to challenge her comfort zone. Posy is intrigued by Jack’s enigmatic nature, while he is captivated by her charm, offering Posy a chance to explore newfound confidence. Although she hesitates to go beyond harmless flirting, her cousin Laura, who is her complete opposite, encourages her to have one last adventure before committing to Tom, her true love. As Posy’s desire for liberation grows, she starts to embrace a hidden side of herself with Jack, adopting an alter ego she calls the Queen of Sin. Unbeknownst to Posy, her entanglement with Jack is akin to making a pact with the devil.