What shall we tell Caroline?

On Caroline’s 18th birthday her parents realize they must tell her something: but what? They themselves know very little about life. Father is the headmaster of a small boys’ school who treats mother like a good chap. Mother for her part responds good naturedly to the harmless advances of the assistant headmaster, who is himself well over the hill. Caroline is a strange and silent girl, but has been secretly growing up. Before they can tell her anything, she tells them she is leaving to enter her own life.