A missing police pistol is connected to a series of recent heists and murders. Its owner Wong (Lee Kwok Lun) vanished earlier while pursuing a suspect in the mountains. His partner Chi Wai (Lam Ka Tung) miraculously returned unharmed. Hotshot cop Ho (Andy On) is in charge of the murder investigation. He knows the only chance he has in cracking the case is to ask for help from his mentor Bun (Lau Ching Wan). Bun is recognised as a gifted criminal profiler until he went mad several years ago. Bun lives in seclusion with his beloved wife May (Kelly Lin) ever since he sliced off his ear at his superior's farewell do.

Wai Ka Fai's penchant for thrillers meets Johnny To action choreography when the original chocolate chinaman Lau Ching Wan plays yet another disillusioned character in "Mad Detective". So mad is he, as Detective Bun, that he sliced off his ear as a retirement gift to his senior.

Why? Oh not much - it's just that he is able to see the 'inner personalities' (or so says the subtitling) of people when he meets them and can accurately judge the disposition and motives of the criminals he is trying to pin down. This makes him a very talented cop but his gift comes with many disadvantages, as his estranged wife (Kelly Lin) and his senior will gladly attest. One man who is interested in his more beneficial qualities is a baffled copper (Andy On) who needs Bun to solve a particularly confusing case of a missing policeman.

Without going into the details of the convoluted plot, one can be assured that "Mad Detective" is as mad as it sounds. The schizo copper Bun is undeniably the highlight of the adventure, what with his post-Tom Hanks hairdo in "Da Vinci Code" and all. It must have been Johnny To's wild idea to display seven different actors playing the multiple personalities of a suspect through the eyes of Bun. What a watch!

However, we are short-changed. While we are entertained by the projection of the coward, the assassin, and the mastermind, the rest of the personalities are not explained. Despite managing to avoid the now timeless cliche seen in movies like "Identity" and "The Sixth Sense", Bun and his tag-along copper seems to be lost in a case with much detail but little depth.

As the mystery unravels, we are persuaded to believe it's a case of calculated gun-swapping (think "Fracture") and double-crossing coppers ("Invisible Target" if you like) but as a action-thriller, "Mad Detective" mostly fails to convey the suspense of following a mystery. Character development through Bun and his tired wife is welcome but other things just seem unnecessary and contrived.

With such decent cinematography and acting, it is disappointing that "Mad Detective" doesn't appear to tie things tighter for the many confused viewers who are probably reading this review to understand the movie. Let's not pretend so - because it hardly matters. Let's just be happy we caught a cameo glimpse of the rarely seen Flora Chan to help us forget the mental turmoil of having to figure out whose gun belonged to whom.