Two fishermen talk about a siren whom one heard singing in the spring. They decide to ask an eremite – a clergyman – what should they do with her as she was not baptised. The eremite advises them to ambush her at the full moon and then deliver her to the local prince of Czersk. The siren comes out of the water at full moon, admires the night sky, and sings. She is seized and locked in the village under guard. The young shepherd looking after the prisoner is enchanted by her beautiful(...)