A young German woman, Emma Wichert, invited the famous detective Drongo to Potsdam for the anniversary of her elderly relative. Emma has known Drongo for many years and is well aware of his unique abilities. That is why she was more interested than others in having an international expert attend the anniversary. As they say, for every fireman. Because a woman’s intuition told Emma that something out of the ordinary could happen at the banquet. And the young woman was not mistaken - in the midst of the feast, the hero of the occasion, Martha, was poisoned with a deadly poison. Drongo immediately begins to investigate and immediately realizes that the killer... was mistaken.