Edward is throwing a dinner party with Binny , his mistress. Aware that she has long been denied those small intimacies that his wife takes for granted - choosing a birthday present for his sister, for example, or sorting his socks - he wants to give her a chance to feel more involved in his life, to socialise with some of his friends (the discreet ones). Things are a little awkward to begin with - a late start and him having to be away by half past ten - but everything seems to be going well. But then some uninvited, and reather forceful guests arrive, and it doesn't look like Edward is going to make it home on time.