From Attractive Fascinante:

In the Royale School, because of his nice name, Ayamoji Kokuei was being targeted by a yakuza’s son, Shirogane Michihiko (real name: Kintarou). Ayamoji began to skip lessons and repeat grades to avoid meeting Shirogane. When they met six years later, Ayamoji drugged Shirogane and they got intimate. Ayamoji left after that and reappeared five years later. Would the two lovebirds finally be together?