A story that revolves around a murder mystery from 18 years ago. Seven teenagers who got into a fight with the local thug are horrified to find out that he has died in the skirmish. The bury his body in hopes that no one ever finds out but a secret can only last so long. Eighteen years have passed, Lin Langsheng (Shaun Tam), Shen Jingyi (Joel Chan) and Xie Jiafu (Anthony Ho) have become adults, each leading their own lives. However, their troubles have only just begun after the body of the thug is suddenly discovered and their crime unearthed. Ruan Lijin (Mandy Wong) of major crimes division is tasked to look into the homicide case. Can the perpetrators face the skeletons in their closets or will they continue to fall into the dark abyss? As Langsheng falls in love with Lijin, the situation becomes more complicated.