Celebrating the success of our project, I start drinking at home with Kanna and the department chief. Before long, both of them pass out from drinking, leaving me alone. Then, the chief suddenly wakes up and leaves without a word, abandoning Kanna behind. Now the room is occupied only by me and Kanna. Kanna, my colleague with whom I've never had any romantic feelings before. Her defenseless body, her bare skin faintly visible through her sheer clothing, begins to subtly stir my thoughts. I struggle to maintain self-control, but the devil's whisper keeps tormenting my mind, gradually breaking down my resistance until I can no longer hold back. The moment I take that first step marks the beginning of this story.