Moscow, summer of 1953. Tanya, an eleven-year old girl, meets a boy, Mitya. Mitya and his family have just returned from exile in the Russian Far East. Tanya learns that Mitya had to leave behind his best friend, a dog called Hector. Mitya is eager for Hector to join him in Moscow, but the adults declare it impossible - a large city is no place for a dog. In an attempt to prove the adults wrong and convince them to bring over Hector, Mitya and Tanya decide to create the perfect home for him - a dog's paradise in an empty sealed room they find in the building....