Because It’s the Rule (2013)

Kyosuke and Mariko are siblings living a simple life, orphaned and alone. When Mariko finds happiness with a wealthy young man and plans to marry, it seems like a turning point for them. But tragedy strikes when Mariko is found murdered, the victim of rape. Devastated and lost, Kyosuke struggles to cope as the police investigation stalls. Then, at a video store, he discovers a new rape video. Renting it, he is forced to relive Mariko's final moments. This ignites a path of revenge against those responsible for her death.