Marple: They Do It with Mirrors (2009)

Sensing danger surrounding her sister Carrie-Louise (Penelope Wilton - Calendar Girls, Doctor Who), Ruth Van Rydock (Joan Collins) enlists the help of old friend Miss Marple. However, after Carrie-Louise’s beloved step-brother is murdered during a dress rehearsal of an amateur stage show, Miss Marple has to draw from her deep understanding of human character in order to unpick the conjuring trick played out by the murderer, and reveal their identity.
They Do It With Mirrors stars Julia McKenzie as Miss Marple and features a rich ensemble cast, including Joan Collins, Brian Cox (The Bourne Supremacy, Zodiac), Elliot Cowan (Lost in Austen, Happy-Go-Lucky) and Alexei Sayle (The Young Ones).