S2·E17 The Night of the Feathered Fury

An organ grinder and his monkey launch an attack: the man is no less than Count Manzeppi, trying to gain a small wind-up bird toy. The toy contains the Philosopher's Stone, reputed to transmute base elements into gold. The race is on as West and Gordon track Manzeppi to his lair. After repeated setbacks and escapes, Manzeppi is forced to escape in a balloon while his henchwoman Gerda is transformed into a gold statue, and the bird and its stone are seemingly destroyed. At the end, the stone reconstitutes itself on the guys' train after they leave for the night.