Retired High Court judge, Sir Fennimore Truscott, has time on his hands and suspicion on his mind. His attractive wife, Margaret, has to endure judgements on everything from the pet dog to a wasp which lands in his toast and marmalade. But today the 'trial' is serious. For years Fennimore has suspected his debonair neighbour, Tom, of rogering — seducing — Margaret. With their only son, Edwin, due to arrive for a rare visit home, Fennimore's long-concealed fears are forced into the open. Who is the boy's father?