From Hero Scans:

Sakuma Shuu is a handsome and capable man whose external successes hide the scars of a youth marred by isolation and brutal bullying. When a chance meeting brings him face to face with the monster that terrorized his school days, Hayami Tsukasa, he is desperate to hide their connection from his colleagues. Shockingly, Hayami doesn’t recognize him, and responding to his desire, he discovers a perverse thrill in having sex with his former tormentor. So begin a story of a game of deception, seduction, and revenge.