With only four partners in her life, Karin Kitaoka experienced her first time at the young age of 16 and is now starting her first year as a working adult. After graduating from university, she joined a mid-sized advertising agency, but became deeply discouraged when she made a major mistake at work just three months in. At that time, a senior colleague invited her out to dinner to cheer her up. He was smart, stylish, and sincerely listened to her struggles about her work errors and difficulty adjusting to life in Tokyo. Gradually, Karin developed romantic feelings for him. Despite knowing he was married, she pretended to be drunk and ended up spending the night with him. Later, she heard from coworkers that he wasn't getting along well with his wife, making her feel even more drawn to him. Captivated by his kindness, she continued their physical relationship, hoping he would eventually leave his wife and be hers. Yet, the approach of this pure and innocent new graduate office lady toward an affair might be far simpler than the risks involved.