Seoul, the present day. In need of money to redeem a treasured family portrait, struggling manhwa artist Jeong Bae takes part in a publishing company's competition for an adult manga with a prize of ₩130 million (US$100,000). Advised that his big weakness is his story-writing, Jeong Bae advertises for a professional writer and ends up hiring the self-important Han Da-rim, with whom he agrees to split the prize money 50-50 if they win. Unknown to Jeong Bae, Da-rim recently lost her job as a sex columnist at magazine Hot Girl — edited by her friend Ma Kyung-sun — where she compensated for her lack of experience with men by copying material from the Kama Sutra to the Kinsey Reports. For the manhwa competition, Da-rim comes up with the idea of a female assassin, Ma Mi-so, who keeps her male victims captive for erotic kicks; without telling Jeong Bae, she models the victim on her twin brother, womanising Han Jong-soo, who shares a flat with her and cannot wait for her to move out. She finally does, which leads Jeong Bae's friend (and fellow competitor) Hae-ryong, who has secretly bugged his flat, to believe they're having an affair. However, from her unrealistic sex scenes, Jeong Bae gradually comes to suspect that Da-rim has never actually "done it", and then realizes she's developed a crush on him.