The Eavesdropper (1912)

Alice takes her little siblings Billy and Kitty to a matinee. They immediately become imbued with the wonderful idea that they are actors. They set up a miniature stage of their own in the summer house on the grounds. They spy upon their sister and her sweetheart Bob, and reproduce their affairs. A quarrel furnishes material for an interesting production, which is a revelation and a lesson to Bob. He goes and makes amends, acting upon the suggestions of the performance.