Copper beeches

"Copper Beech" is a story from the "The Adventures of Sherlock Holmes" series.
Sherlock Holmes is approached for help by a young girl, Miss Violet Gunter, who earns her living by working as a governess. For a generous fee, she must fulfill a series of rather strange requests from her employers, Mr. and Mrs. Rucastle. One day, the girl notices that the owner is constantly visiting the closed wing of the house, carrying a small bag with him. The girl suspects that the case is dirty and asks the detective for help.