I'm a freeter living with my older brother and his wife. My sister-in-law, Karen, is slender and incredibly beautiful. One day, my part-time job ended early, so I returned home and unexpectedly found her in the living room with her hands on her breasts and crotch. Shocked by the sudden sight, I panicked and quickly ran back to my room. That night, while I was soaking in the bathtub, my sister-in-law suddenly appeared in the bathroom completely naked, leaving me stunned and confused. From that moment on, my relationship with her began to deepen in unexpected ways.