Seven-year-old Polina and her 13-year-old sister Nastia live and breathe ballet. Both of them are studying at the Boris Eifman Dance Academy in frigid Saint Petersburg. They’re currently awaiting their grades to find out if they’ve done well enough to be promoted to the next year, with Nastia lovingly guiding he little sister through the process. But in the meantime, Nastia also has to deal with the high demands that the academy places on its students. The gorgeously styled shots are sometimes calm, even clinical, and sometimes warm, lively and funny.

• Documentary