Zachary whacks Ethan in the face with a stick in a park, and the parents want to sort things out. Ethan's, Penelope and Michael (Jodie Foster and John C. Reilly), invite Zachary's, Nancy and Alan (Kate Winslet and Christoph Waltz), over to settle matters and what seems to be a simple chat to set up positive interaction between the boys turns into much more as the guests stay to eat apparently horrific cobbler, drink coffee, spew bile, drink, and, to the annoyance of everybody, answer countless phone calls.
Sure, some of the satire works at times, and the performances are decent, but it's not really worth it. Whit Stillman does this sort of thing better. "Carnage" is certainly not worth spending a bunch of money on, especially if you're someone who doesn't see a ton of movies. C