Altman's unexpected venture into Agatha Christie territory works a treat. The setting is an English country house, the year 1932, and the many and varied heirs to the McCordle family inheritance congregate for the weekend to bag pheasants, ruffle some feathers, and suck up to the old man (Gambon). Each has a maid or a valet in tow. Upstairs, everyone knows his or her place, and social proprieties are strictly observed. Downstairs, as above, so below, where the visiting servants are even known by their masters' names. Yet behind this orderly facade resentments fester, and when McCordle is found dead over his brandy, there's no shortage of suspects. We all know that Altman can throw a party, but it's a pleasant surprise how much respect he's accorded Julian Fellowes' witty, intricate screenplay, from an idea by Altman himself and actor/producer Balaban. The family relationships could be a bit clearer, but the danger that the audience might get swamped by the several dozen speaking parts is circumvented by a glittering, instantly recognisable cast, plus a couple of tour guides: first, Balaban's droll Hollywood producer, researching the mysteries of British etiquette for his next B-movie; then Kelly Macdonald's novice personal maid, getting pointers from her splendidly barbed mistress (Smith) and from a 'seen it all before' domestic (Watson). Altman has such fun satirising the affectations and casual cruelties of the class system, it's almost a shame when he finally gets down to plot machinations - whodunit is the least of it.