Benny Chan's Heroic Duo features an unlikely duo working together to crack a very mysterious case. Officer Ken Li (Ekin Cheng) learns that a fellow officer has committed a horrible crime. However, the perpetrator has no recollection of having done it. Ken Li seeks help from a former psychiatrist and current prisoner Jack Lai (Leon Lai). The pair soon learns that a master hypnotist might be behind this and several other disturbing events. ~ Perry Seibert, All Movie Guide