Captain Vašátko of the criminal police and Horác, a painter, bohemian, and amateur detective, escape the stresses of life by going to the river to fish. Horác befriends a young neighbor who is found dead one day. Everything points to suicide, but Horác is still suspicious, so he embarks on an investigation, even resorting to unacceptable tricks that ultimately land him in a very unpleasant situation. Fortunately, his friend Commissioner Vašátko intervenes, understanding his friend's extravagance...
