The Sex Detectives have got a new request from Kasumi Lovecraft, a detective from New York. Hatenashi’s manager, Maebari, tells him that he has been offered a job as an actor. Hatenashi gets in a good mood with Miona, a production staff member, during a commercial shooting and asks Miona out on a date. The date goes well and the two make love at Hatenashi’s apartment. However, on the way back from investigating the case with Kasumi to track down the missing Kido, the Director-General of the Police Agency, Hatenashi witnesses Miona secretly meeting with Harigata, a client of the commercial.

今度は恋愛だ！セックス探偵・ハテナシ一世一代の大恋愛物語！本業である役者としての仕事が舞い込んだハテナシは、現場で働く美緒奈に一目惚れ。愛を育む二人だったが、そこにはハテナシ抹殺の罠が仕掛けられていた！新キャラ続々登場の最新作！