During World War II, Eric Lomax is a British officer who is captured by the Japanese in Singapore and sent to a Japanese POW camp where he is forced to work on the Thai-Burma Railway north of the Malay Peninsula. During his time in the camp as one of the Far East prisoners of war, Lomax is tortured by the Kempetai for building a radio receiver from spare parts. This is apparently due to his falling under suspicion of being a spy for supposedly using the British news broadcast receiver as a transmitter of military intelligence. His only intention, in fact, had been to use the device as a morale booster for himself and his fellow prisoner-slaves. The torture depicted includes beatings and waterboarding.
Years later and still suffering the psychological trauma of his wartime experiences, with the help of his wife Patti and best friend Finlay, Lomax decides to find and confront one of his captors who had escaped prosecution as a war criminal. He returns to the scene of his torture after he has tracked down Japanese secret police officer Takashi Nagase "in an attempt to let go of a lifetime of bitterness and hate".