They were 6 and 8 at the time he wrote it, five years after the famous suicide of their mother, Sylvia Plath. In keeping with this dark history, Hughes' books for kids tend to tell ominous, sometimes preachy fables about ambition, despair and people's disregard for nature and one another. Earlier in the play, he discovers a race of innocent savages, cuts down their native forest and sets them to work in car factories. Similarly, the last play in the book is a bitter story about the Nativity from the point of view of the innkeeper and his wife who, to their endless shame, sent the holy family to sleep in the cow shed. Another play, a version of the Orpheus myth, begs to be read in light of the poet's personal history.
Nothing is free.
Everything has to be paid for. For every profit in one thing, payment in some other thing. For every life, a death. Even your music, of which we have heard so much, that had to be paid for. Your wife was the payment for your music.