Senior psychiatrist Ko Lap Yan (Alex Fong) of Yan Wo Hospital, having successfully helped Senior Inspector Chung Kwok Bun (Ben Wong 黃 智賢) solve several criminal cases with his professional analyses on criminal psychology, is invited to work in a new department, the Department of Forensics Psychiatry.
Yan suffers near depression after the death of his wife, Mandy (Kate Tsui). He finds his strength again with the support of his friends Sam (Ram Chiang 蔣志光) and Leung Kai Wing (Edwin Siu 蕭正楠), a new intern at Yan Wo Hospital. Yan also finds new romance with his work partner, psychiatrist Cheuk Wai Kiu (Yoyo Mung 蒙 嘉慧). Together, the gang of four help out the Criminal Investigation Department led by Bun and his new subordinate, Lam Chung Yan (Tavia Yeung 楊怡).
Aimee Chan (陳茵媺), Oscar Leung (梁烈唯), Christine Kuo (苟芸慧), and Oceane Zhu (朱璇) are also new additions to the cast.