Three Keys from the Fourth A

Once upon a time, on New Year's Eve, the Secret Santa disappeared…
Lea, Agasha, and Luka are just ordinary students of the fourth "A" of the most ordinary school in the north of Moscow. Lea is an aspiring figure skater and dreams of a dog, specifically a corgi; Agasha loves turtles; and Luka is a true chess genius. Two weeks before New Year's, something incredible happens to the kids: the "Secret Santa" sends Lea a key and a mysterious note with the word "SOS". The young detectives are convinced that it's a call for help, and the heroes begin their investigation!