Chen Kun, known for his precision and seeming lack of emotion at work, has earned a reputation among colleagues. Some call him a soulless machine; others call him Agent 005, “the Fifth of the Great.” His new assignment is connected to the mysterious disappearance of the sister of a major Chinese businessman in Kazakhstan. However, it quickly turns into a major investigation of a series of murders, in which the Chinese woman is not the first victim. There are no clues at the crime scenes: no video recordings, no digital traces, no fingerprints. The police of China, Russia, and Kazakhstan have to combine their efforts to catch the killer, who leaves behind a nylon heart in the bodies of the victims.