Sam Rockwell and Saoirse Ronan gel really well together in this rather entertaining spoof of all thing Agatha Christie. The latter is the newbie constable "Stalker" - an enthusiastic young woman who is saddled on the experienced, gin-loving, inspector "Stoppard" when the pretty unlikeable film director "Köpernick" (Adrien Brody) is beaten to death with a sewing machine! It turns out that he had just been engaged to direct a big screen version of the legendary "Mousetrap" play that had just celebrated it's hundredth performance at London's Ambassador's Theatre. What now ensues is a really engaging whodunit with flashbacks galore as the two police officers have to learn to trust each other as well as to handle the high drama amongst a cast of thespians, an avaricious producer and, of course, a publicity seeking police Commissioner. Rockwell delivers strongly as the rather laconic and disillusioned officer (he reminded me a little of Johnny Depp's "Abberline" in "From Hell" from back in 2001) and Ronan brings plenty of amusement (and courage) to her role as his aspirational sidekick who is always jumping to conclusions. As ever with Christie stories, you just know that the perpetrator of the crime is going to be the least important character so there's not oodles of jeopardy here, but it ends well with all assembled in a creaking stately home where it all ultimately falls to the author - "Moaning Myrtle" herself - to solve her own mystery. Tom George has assembled a decent supporting cast with both Harris Dickinson quite effective as a rather effete Richard Attenborough and Ruth Wilson as the shrewd theatre producer "Petula" and they help to deliver a pace and humour that is enjoyably amiable for just over ninety minutes. I've sat in the Ivy restaurant opposite this theatre for many a year but have never actually seen the play. A bit like with this film, you mustn't disclose the ending or maybe you'll be next... Good fun!