‘Mad’ barely covers it: at a retirement party for the chief of police, Detective Bun slices his own ear off as a leaving present. He has his uses though, namely his uncanny ability to see into people’s inner personalities and emotions – which makes him ideal for an investigation into murders committed with a missing police gun. Johnnie To’s latest is another stylishly wrought crime saga, studded with endearingly nutso moments. But despite Lau Ching Wan’s imposing turn as the gifted, loony copper, both the plot and characters are sketchily drawn. Through Bun’s extraordinary eyes we see a tubby suspect’s psyche embodied as seven diverse personas, including that of a power-suited femme. Bun himself, on the other hand, remains stubbornly one-dimensional.