At the National Opera House in Kiev, Ukraine, a group of masked gangsters suddenly broke into the performance hall and held hundreds of musicians and audiences hostage. Not long after, the Ukrainian special police force arrived quickly and broke in according to the established tactics. At the same time, several mysterious people put on the epaulettes of the special police force, sneaked into the opera house during the chaos, and rescued the trapped American ambassador. Although the male protagonist "Nameless" (John David Washington), one of the mysterious men, successfully completed the task once, he was involuntarily put to death. When he woke up again, he was told that he had lost his original identity and would join a secret organization called "Tenet" to carry out a major task to prevent the destruction of the world. As early as in the opera house, he witnessed a strange phenomenon of reversing bullets. And the task now underway seems to be closely related to the reversed bullets and even the reversed time. What is destined to happen will happen, and what causes will result...