Yuzuru Shiga lives an ordinary life, spending most of his time with his high school archery team along with his girlfriend, Satomi. His relatively mundane life gets complicated, however, when his aunt dies under suspicious circumstances and his cousin and fiancée, Azusa, re-enters his life. While Yuzuru sees her as a mere relative, she is dangerously serious about their future marriage and will not tolerate the threat of Satomi. As things continue to get ever stranger since Azusa's return, Yuzuru now has to decide whether his relationship with Satomi is worth the potential danger.