A horde of beavers have launched their attack on Vienna. They started out by killing a little forest on Danube Island. They felled mostly the big trees and spared only the little ones.
Once nearly extinct, now a protected species, the beavers are thirsty for revenge. Their hunger is unsatiable. Chop, chop, chop! the people hear them working during night. They must be building a big dam somewhere to flood Vienna! Nobody has discovered it yet. The Danube in the meantime has risen to an alarming degree.