An innocent man is released from prison after 12 years and tracks down the witnesses who lied about him in court.

In this drama, a frustrated upper-class writer decides that he will find real inspiration by examining his subjects first-hand. This leads him to begin wandering about the seamiest side of town where he witnesses a murder. When an innocent man is arrested, the writer refuses to assist him as the knowledge that he has been "slumming" could destroy his career. The young man is sentenced to 15 years in prison.

When John North, a budding author, pulls the communication cord of a late night train that is taking him away on a weekend with his publishers wife, he sets in motion a series of events that lead to a train crash, a murder and a police man hunt, but all is not what it seems.