The Adventures of Petya and the Wolf. The Case of the Lazy Island

Koshchey receives an invitation from distant relatives: in honor of Memorial Day, an annual week-long carnival is planned in faraway Mexico. Koshchey has never been on vacation, so he goes to visit, leaving the household to Kolobok.
But a week passes, and there is no news from Koshchey, and he does not return! Worried Kolobok seeks help from Petya and the Wolf.