Yagami Ryoya, an ordinary high school boy with no particular redeeming qualities, saved the lives of the school's idol twin sisters from a violent thug. That was the beginning of their sweet yet abnormal "repayment"─. Reona and Riona close the distance, affirming his every move and spoiling him to the absolute limit. However, their love is a "yandere" obsession that goes way beyond just being "super heavy"...!? Dragging in his family, his environment, and everything else around him, the twin sisters completely seal off Ryoya's escape routes. They are undeniably cute, but there is nowhere to run. What will become of Ryoya's fate now that he is locked onto by a 100% pure desire for monopoly!?