Wealthy industrialist Archibald Sterling collapsed and died in his study after drinking his customary evening brandy during a small private gathering. The autopsy revealed a lethal dose of cyanide. The four people present that night—his wife, son, daughter, and business partner—each harbored grudges against him. The brandy decanter had been left on a sideboard, accessible to all. With the doors locked and no outside intruders, the killer must be one of these four. Only the right combination of motive, means, and opportunity will reveal the culprit.