Now Reza's play has come into the misanthropic hands of her fellow Parisian Roman Polanski and the match is perfect. Polanski has dropped the "God of" from the title but otherwise retained the claustrophobic setting of a single apartment, where two fortyish couples meet up through a need to talk about Zachary. He's the 10-year-old son of one of them, who has had a playground row with Ethan, the other couple's 10-year-old, and knocked out a couple of his teeth. The play exists in two settings, one French, as originally produced; the other American, as presented on Broadway, and it's the latter that Polanski and Reza have adapted for the screen.
The comfortable, tasteful but not ostentatious flat belongs to Michael and Penelope Longstreet, parents of the victim, Ethan. Michael (John C Reilly in rumpled teddy bear mode), it transpires, is something of a roughneck, a salesman of kitchenware and sanitary equipment, hypergamously married to the prissy, humourless Penelope (an aggressively thin-lippedJodie Foster). A concerned liberal, she writes earnest books about Africa's problems and is bent on improving Michael and elevating herself. She talks in the argot of self-improvement texts, wears her heart on her sleeve and displays her culture on the coffee table.
The visitors are the more confident, socially somewhat grander Cowans: Nancy (Kate Winslet in edgy designer clothes) is an investment broker, Alan (Christoph Waltz performing a variation on his SS officer from Quentin Tarantino's Inglourious Basterds) is a suave, brutal, corporation lawyer, constantly on his mobile about the defence of a dodgy pharmaceutical company facing a class action. He's the one who worships "a god of carnage".