Markuss unravels the tragic story of the life of lonely English teacher Polina Klochko when her son Mark is kidnapped from kindergarten. The story unfolds when five years later, in a newscast, she accidentally spots Mark in the crowd. Polina resumes the search for her son with the help of ex-police officer Denis Denisov. Whilst investigating the boy’s disappearance they discover a dangerous gang that kidnaps and sells children to adoptive parents abroad. Denisov soon faces a bigger challenge and a terrible dilemma: how can he help the woman he loves to reunite with her son if life of his only daughter is at stake?