"Marcus" is a Ukrainian-Latvian detective melodrama series that tells the story of a English language teacher named Polina. The heroine lived a peaceful life, but one day she woke up in a real nightmare. Someone kidnapped her little son, Marcus, right from the kindergarten. Five years later, while watching a broadcast from the Latvian capital on one of the TV channels, she accidentally sees her son among the crowd. Polina resumes her search, now with the help of a special agent.