A fairy tale with historical elements takes place in the time of Rudolf II. And during the Thirty Years' War. The main character is the water sprite of Tobijáš of Berounka, who will accept the invitation of the owner of the Mníšecký estate Vratislav III. from Mitrovice and settled in the castle pond.
The poetically tuned narrative is set in the natural scenery of Mníšecký ponds and Brdy hills. It is incorporated into it almost encyclopedically detailed description of many fish and birds - as well as historical personalities, such as astronomer and mathematician Martin Bacháček of Noumemice, Men Mníšecký manor or Swedish soldiers The plot develops from a peaceful to lyrically idyllic atmosphere into a number of dramatic moments of human and historical, and with the support of statements full of wisdom life will lead the reader to understand how everything is connected with everything. To be aware of the sacredness of life. The book attracts older children and their parents.