Marple: Greenshaw's Folly (2013)

When old family friend Louisa Oxley visits Miss Marple one stormy night seeking help, Miss Marple decides to send her and her son, Archie, to safety at the labyrinthine estate of Greenshaw's Folly, owned by Miss Marple's good friend Katherine Greenshaw, an eccentric botanist and the last surviving Greenshaw. Louisa becomes Miss Greenshaw's secretary, and quickly attracts the attention of the gardener Alfred Pollock and actor Nat Fletcher. Things turn sinister when the Folly's faithful butler, Walter Cracken, is killed in what appears to be a tragic accident. Then a guest at the house, Horace Bindler, disappears without a trace. Miss Marple is convinced all is unwell, and her suspicions are confirmed when Miss Greenshaw herself is brutally murdered. Suspects are everywhere, but none can imagine the secrets, both past and present, which Miss Marple uncovers.