The little genius, Armand de Trouville, is dead. He's left no heirs, no will, no beneficiary, and no relatives. Prior to Trouville's move to Milwaukee in 1936, his life is a blank. His business associates ask the Milwaukee police for help in finding any heirs, and Detective Lieutenant Joe Sonntag takes on the task as a courtesy. Trouville's death at 68 from heart failure was not unusual. But something about it stirs suspicion in Sonntag's chief.
