Over ten years ago, I happened to meet Akane. She had a slender build—not too thin—with breasts and hips that were incredibly alluring. Introduced to me through a mutual acquaintance in the adult industry, we weren't particularly close, but her calm personality left a good impression. What stood out was her deeply lustful nature and strong masochistic tendencies—she possessed a profound desire for submission. She never spoke about its origins, and I never pressed her for personal details. Still, I could sense that something inside her remained unfulfilled. Outside of work, we occasionally became physically intimate and shared meals together, though we were never lovers. Our strange relationship lasted for years. In my youth, I was a womanizer who frequented brothels, and at one point traveled the world seeking out streetwalkers, as if trying to mark every country on a map. But after suffering a serious illness, my relationships with women ceased entirely. Even Akane, with whom I once had wild sex, is now merely a karaoke companion. Recently, by chance, I took Akane on a hot spring trip after not seeing her for a long time. Her role on this journey? My mistress. More specifically, my sex slave.