Into Thin Air (2005)

Original title: 人間蒸發

Ko Chung Ching (Michael Miu), an ex-policeman, quit his job to set up a private investigation company two years ago, right after his son Tsun Sing went missing because of a slap while Miu was searching for the "Rose Killer". His subordinates include Man Kai Ching Super (Power Chan), Man Tai Po (Bernice Liu) and Lam Yan Yan (Vivien Yeo).Kenneth Ma plays the cop who takes on Miu's "Rose Killer" case. Ching works and carries on looking for Sing. He meets Lai Siu (Melissa Ng) the manager of a group of part-time actors. She learns by chance that she was involved in Sing's disappearance, and as such feels guilty, so agrees to help find Sing. She uncovers a few clues and finds out Sing's disappearance is connected to Sing's divorced wife and good friend Lau Kwok Wai (Wong Chi Yin). Ching is shocked by the truth...