Majka and Kacper are a young couple going through their first serious crisis. After a squabble with her boyfriend, she decides to get a tattoo on her belly [hence the title of the movie] as a sign of her independence. Kacper is not pleased with Majka's decision, which causes more tensions between them and gets more people involved, mainly because of the nosy next-door neighbor who listens to every word they say through "paper-thin" walls; meanwhile, Kacper's father feeds him bad advice, being a bitter man himself, still dealing with a divorce him ill advice being a bitter man himself 15 years after his divorce.