Wei Rong tracked down an enigmatic man who had been using a dead man's cellphone. She initially suspected him of killing her best friend, Zong Si Ning, and harassing her aunt, Zong Feng. She later learned that the man, Ma Dong, was investigating Si Ning's death, which he believed was connected to his mother's suicide a year earlier at her aunt's hospital. Together, they retraced Si Ning's steps before his untimely death. They discovered a secret so devastating it would've destroyed their families if Si Ning had lived to tell it.