Walter and Susan arrive at the zoo one hot summer's afternoon. They're there to see a lion, but in the end it is not the animal which is important but the other people whom they meet. Among them are John, Susan's former husband, and Laura, John's present mistress, with her children. Mrs. Elliott who has been to see Laura's Harley Street husband is there with her son .... and so is is P.C. Hart.
They have each come for different reasons, but now their paths seem about to cross. Or will they find that the animals are not the only beings trapped behind bars?