Far, on square land

In the far corner of the universe there is a planet inhabited by rabbits. Their civilization is largely similar to ours. They even have such familiar and relatives. For example, the head of the Rabbit family (such a surname) is the name of Anton Ivanovich, his wife is Svetlana Sergeevna. They have a couple of rabbits: a fifth-grade student Anya and her younger brother Vitalik.
We get acquainted with the Rabbits family at a crucial moment: they want to exchange their cramped apartment for something more spacious. The undertaking succeeds, but this gives rise to a chain of incredible incidents: the younger rabbit is looking for a pirate treasure, Anton Ivanovich is chasing his own reflection, and Anya acquires her prince