They Do it with Mirrors

Miss Marple senses danger when she visits a friend living in a Victorian mansion which doubles as a rehabilitiation centre for delinquents.

Her fears are confirmed when a youth fires a revolver at the administrator, Lewis Serrocold.

Neither is injured. But a mysterious visitor, Mr Gilbrandsen, is less fortunate - shot dead simultaneously in another part of the building. Pure coincidence? Miss Marple thinks not, and vows to discover the real reason for Mr Gilbrandsen's visit.