The famously prickly Isomura-san has made a vow. That vow is—I WILL NOT FALL IN LOVE! In fact, Isomura-san is a Stage 5 Clinger who can't get enough of guys. In the past this habit caused him to hurt his live-in niece Hina, and so he has vowed NEVER TO FALL IN LOVE UNTIL HINA IS LEGAL. Thus he plays the prickly part of a prickly person, pushing others away. But then, one day, Hina said: I WANT TO BECOME A DETECTIVE! And things got flipped, turned upside down. Enter Uzuki, the Detective Instructor. It's love at first sight for Isomura-san, so what's a fraudulent loner to do?! He's completely at Uzuki's mercy! Is a lovey-dovey victory on the cards? Or...