One day, Murata finds a woman drunk and collapsed on the street and, unable to leave her there, takes her home. Unable to resist the woman's defenseless state, he makes a move on her. Later, he is invited to a drinking party at the home of a senior who helped him out in his club activities during his student days, but the woman there is none other than the woman from that night! Of all people, she is the senior's younger sister, Megumi. He tries to act as if it's their first meeting with a smile, but Megumi suddenly grabs his hand and whispers, "I haven't forgotten," sending chills down Murata's spine. What if the senior finds out about that night...? While Murata is filled with anxiety, Megumi begins to toy with him without regard for her brother's presence.