In the West End of 1950s London, plans for a film version of a smash-hit play come to an abrupt halt after a pivotal member of the crew is murdered. When world-weary Inspector Stoppard (Sam Rockwell) and eager rookie Constable Stalker (Saoirse Ronan) take on the case, the two find themselves thrown into a puzzling whodunit within the glamorously sordid theatre underground, investigating the mysterious homicide at their own peril.