When a man is found at the base of a mountain with his skull crushed, it looks like he slipped, or did he commit suicide, or was he pushed? Well it falls to detectives "Jang Hae-joon" (Park Hae-il) and his young sidekick "Soo-wan" (Go Kyung-Po) to get to the bottom of it. They are suspicious enough, but the only realistic suspect is his younger widow "Song Seo-rae" (Tang Wei) - but she has an alibi. She looks after ageing grannies and they swear that she is the milk of human kindness. Gradually, the older policeman begins to obsess a little about her. He stakes out her apartment at all hours, follows her - and she knows it too. Is she playing with him? Toying with him? Skip forwards a few years and he and his wife are in a market where they encounter "Seo-rae" and her brand new husband - a man on the run from folks he owes a great deal of money to. An embarrassed exchange follows before they leave, only for the officer to discover a few days later that there is a corpse in swimming pool and yep, it is that of her new husband. Is she a serial killer? Is she completely innocent? The inspector is convinced she is behind it, but he cannot prove it and his personal and increasingly destructive fascination with the woman, along with her own considerable skills at deception and manipulation lead us to a denouement that, well, certainly surprises. The acting here is strong, especially the young Tang We; there is some humour and we are also given a few clues, ourselves, as to just what might have happened - and whether or not she might be (or not) the perpetrator - there are red herrings a-plenty here. Jung Young Sook offers quite a charming contribution as the ageing and ostensibly corroborating granny "Hae-dong" too. The plot has loads of twists and turns, and essentially offers us two stories rolled into one. It's quirkily entertaining - and we are never quite sure! I really enjoyed this.