It is New Year's Day of 2006, more than a year after the events of Night Watch. Anton Gorodetsky, theprotagonist of the first film, finds himself in the middle of an approaching conflict between the Light and Dark Others, who are still bound with an uneasy truce. Anton is still a Night Watch operative, now working with his trainee and romantic interest,Svetlana. As his son Yegor has now become a Dark Other, Anton is forced to secretly destroy evidence of Yegor's attacks on normal people, which violates the treaty, leaving the Night Watch unable to sentence Yegor.
To redeem for his previous mistake, an attempt to use a witch's service to kill the unborn Yegor (shown in the beginning of the first film), Anton seeks the legendary Chalk of Fate, a magical chalkthat could rewrite history, which was onceTamerlane's property and one of the main reasons for his numerous military successes.
Meanwhile, Zavulon, the leader of the Dark Others and their Day Watch, is waiting for Yegor's birthday. At the birthday, Yegor would become a Great Other and acquire the power that would allow the Dark Others to break the treaty (which is only supported because the Others fear that the two sides will destroy each other). Zavulon's gratitude to Anton for covering Yegor's violations of the treaty doesn't stop him and the Day Watch from attempting to frame Anton for murder and bring him in front of the Inquisition. They succeed, despite the efforts made by Geser, the head of the Night Watch, to protect Anton from the Dark Others by putting him in Olga's body. While in her body, Svetlana confesses that she loves Anton to the person she thinks is Olga, which pushes their relationship forward. This happens despite Svetlana's initial anger at Anton for not telling her that he was in Olga's body.