Mirrors deceive - Agatha Christie

Miss Marple goes to live in a large country mansion, in which a reform project has been set up, which includes about two hundred juvenile delinquents whom the owners of the project seek to rehabilitate.

Miss Marple came to this strange place in response to a request from one of her old school friends, after this friend had a strange feeling of danger to her sister residing in this mansion.

And now the crime occurs. Is this the danger Mrs. Van Riddock feared? And what will Miss Marple do?