Ivan is a simple, good-hearted man who wakes up in his apartment and notices a mare named Kasia just outside his window. Being a kind soul, he keeps her and takes her around the city. What is that mare capable of, and where do you find a shelter for her? Kasia becomes a problem for Ivan and the subject of all kinds of speculation. But unlike everyday problems, you can easily get rid of it by letting go of the reins.