Does it count as a locked-room mystery if the “room” is a moving train? Agatha Christie’s 1934 whodunit certainly fits the “this murder sure seems impossible” criterion of the genre. Ah, but possible it is – it’s one of the queen of mystery’s biggest jaw droppers – adapted for the stage by Ken Ludwig (Lend Me a Tenor), directed by Jenny Lavery, and starring, naturellement, Christie’s iconic Belgian detective Hercule Poirot, played on the Topfer stage by Steven Pounders. Set in the 1930s aboard one of the world’s great luxury trains, expect your little gray cells to spark to the production design as well as the sleuthing. – Kimberley Jones