An ex-cop searches for a missing teen as a favour to her parents.

When Rain, a beautiful university year 4 student receives an SMS on her mobile phone - "Do you know what the 19th Gate of hell is?", the nightmare begins for her. It is not too long before she realizes that she is unwittingly trapped in a terrifying mobile phone game from hell and this game is larger than life.

One suspects writer-director Carol Lai may have harboured some Black Swan ambitions with a tale that also centers around a stage practitioner who embarks on an unwitting destructive journey when playing a role to die for. The Second Woman, whose Chinese title Romance Riddle may hold better clues as to how this film developed, being more of a guessing game that threw constant clues rather than a overly romantic film about twins falling in love with a man who decided it's perfectly OK to string both women along, until he discovers that this spells double trouble.