There are three of them, brothers and a sister. Each of them is cosily settled into his or her adult life, or so it seems. Then they decide to give a party in honour of their father, the honourable professor emeritus Ellsworth Humelsine. But Ellsworth has disappeared. Following his trail, Ruby, Virgil and Seymour will eventually meet up with a man who has refound his youth and who will give them a lesson in living.