In Los Angeles Chinatown in 1937, Constable Jack resigned and became a private investigator because of his dissatisfaction with the darkness inside the police station. On this day, a woman who claimed to be Mrs. Morale asked Jack to investigate her husband's affair, and Jack readily accepted. Jack discovered that Hollis Morale was originally the local water conservancy chief engineer and was arguing with local farmers over the construction of the dam. Then someone gave Jack some photos that proved Morale's affair, but the real Morale's wife Evelyn came to the door the next morning and asked Jack to stop investigating Morale.
Things are getting more and more blurred, and Jack is determined to keep track of it. Unexpectedly, Hollis Morale died in his own pool soon. The local police believed that he had died by suicide. The astute Jack felt that things were getting more and more difficult. In the course of his investigation, unbelievable truths surfaced one after another.
