[Reducing Mosaic]JUR-139 On the eve of my proposal to her, I indulged in unprotected sex with my childhood friend who smiled seductively and said, 'Starting tomorrow, it'll be W-adultery...' Tsumugi Akari.

I'm an ordinary office worker, currently dating a coworker named Nao. I've been thinking about proposing to her soon—actually, tomorrow. After work that day, while discussing dinner plans with Nao, I received a call. It was from my childhood friend Tsugumi, who said she had lost her wallet and needed help. I lied to Nao, saying a male friend was in trouble, and headed to Tsugumi's place. I found her in a mess and took her to a hotel. But as I tried to leave, she grabbed my arm and asked me to stay a little longer…