Animal conservationist Stefan Schönewald is killed in a wild river, due to his sabotaged kayak paddle, while observing beavers. Tobias Hartl and Danner look into the neighboring fruit growers, whose harvests are threatened by beaver lakes, notable Sepp Langenbach; Stefan's heiress girlfriend Giselle Marquard, whose father payed their bills, and environment official Julia Ried, who was his ex and ally in beaver conservation, and discover some surprising reports between he above, yielding potential motives.
—KGF Vissers