Two peasant children, Mytyl and Tyltyl, are led by Berylune, a fairy, to search for the Blue Bird of Happiness. Berylune gives Tyltyl a cap with a diamond setting, and when Tyltyl turns the diamond, the children become aware of and conversant with the souls of a Dog and Cat, as well as of Fire, Water, Bread, Light, and other presumably inanimate things. The troupe thus sets off...