V Mariboru potekajo zadnje priprave na kongres na temo ekologije, ki ga organizira ambiciozna direktorica inštituta Ema Žnidaršič. Poseben gost je mednarodno uveljavljeni strokovnjak, ki že leta predava v ZDA, Peter Divjak. Čeprav je bil začetek druženja kongresnikov idiličen - pod vodstvom Emine sodelavke Marte Jenko so odšli na izlet na Pohorje - pa na jutro velikega dogodka Drava naplavi truplo glavne zvezde kongresa, profesorja Divjaka. Znaki kažejo, da je Divjak umrl nasilne smrti, zato se inšpektor Martin Vrenko z novim sodelavcem Tadejem Krajncem poda v iskanje storilca.
In Maribor, the final preparations are underway for a congress on the topic of ecology, organized by the ambitious director of the institute, Ema Znidarsic. A special guest is Peter Divjak, an internationally renowned expert who has been lecturing in the USA for years. Although the beginning of the meeting of the congressmen was idyllic - under the leadership of Ema's colleague Marta Jenko, they went on a trip to Pohorje - but on the morning of the big event, the body of the main star of the congress, Professor Divjak, washes up on the Drava river. The signs show that Divjak died a violent death, so Inspector Martin Vrenko and his new colleague Tadej Krajnec set out to find the perpetrator.
