Kuro no Gyakushuu

A young boy endures daily torment at the hands of his school rival, who humiliates him in front of their classmates. Feeling powerless and consumed by anger, he devises a twisted plan for revenge: instead of confronting his bully directly, he decides to target the person closest to him—his rival's girlfriend. Through manipulation and calculated charm, he manages to seduce her, believing that this betrayal will strike a deeper blow than any physical fight could.

However, as the affair progresses, the lines between revenge and genuine emotion begin to blur. The boy finds himself entangled in a web of lust, guilt, and unexpected feelings, while his rival remains oblivious to the betrayal unfolding behind his back. What started as a cold act of retaliation soon spirals into a dangerous game where everyone involved risks losing more than they bargained for.