The construction of the new dam deprived the ferryman Ryba of his trade. The new dam replaced the ferry. However, Ryba's ancestors were ferrymen and the old man would have liked his two sons to take up the same profession. But Joseph is an indecisive weakling and Karel found work on the dam. That's why old Ryba drove him out of the house. The persistent rain brings Ryba miserable joy. The man knows well that a sudden flood can endanger the unfinished dam. In his fanatical hatred, he forgets that the water from a broken dam would sweep away his house and his daughter-in-law and sick grandchild in the first place...