I've been bullied for years by my beautiful but domineering older sister. Now that she's about to get married, I'm finally taking revenge. I discovered her dark past—she used to be a delinquent who engaged in perverted acts—and I'm using that secret to blackmail her into a forced relationship. I've secretly recorded and studied every one of her sexual encounters, analyzing exactly how she feels and cums. Now the time has come to put my research to work. I'll make her experience every ounce of humiliation and pleasure she deserves, repaying her years of cruelty with interest.