3 boys decide to go skinny-dipping at the pond and invite their friend Honza (Michaela Doubravová, 11). But Honza is actually girl; she believes that she is a boy and doesn't know the difference between boys and girls. They take off their clothes and the boys start laughing. The girl runs off (full nudity from side/back).
The same boy and a girl (9) get undressed in front of each other while changing for swimming, girl shown shirtless. The girl asks to see the boy's penis. He complies, but this is not visible to us. Small boy spies on them.