One beautiful summer morning in a small Russian country town, six-year Marussya wakes up to the sound of her parents arguing. When her mum departs 'for the city' with no set date for return, and her dad suggests that he and Marussya take a train to Lake Baikal, Marussya is determined to delay the departure. She improvises a fairy tale, in which her mum, as a school-age girl, sets off on a dangerous journey to an imagined Russian past to save Marussya's dad, then her schoolmate.