Police discover Eva Nejtková dead in her apartment and her husband Zdeněk unconscious from a shotgun wound. Captain Hora leads the investigation, noting that the killer struck Eva fatally and shattered her large aquarium, yet carefully transferred the goldfish into a smaller tank. Initial suspicion falls on Zdeněk’s apparent suicide attempt, but financial records and the absence of drugs at the scene shift focus. Detectives trace psychotropic medication supplies to Eva’s dealings with local addicts. As they question these “práškaři,” they uncover a network of illicit sales and potential motives tied to debts and blackmail. Clues from the supplier’s arrest and addicts’ testimonies gradually reveal whether Eva’s murder was linked to her clandestine drug trade or if a more personal betrayal lies at the heart of the crime.