Royal Guard (2002)

Plainclothes cop Wen is assigned to protect Lai, a famous socialite who witnessed the murder of her husband by the notorious twin brother assassins. After some close calls, Lai finds herself falling for the married Wen, whose marriage is on the rocks. The case soon turns personal for Wen, when his son is kidnapped by the twins as ransom for Lai's life. (Tai Seng)