Based on" the 1907 autobiography, "Father and Son", by Christian fundamentalist and naturalist Edmund Gosse, but Dennis Potter adapted only one section of the book, adding much material of his own invention. With a literal belief in the Old Testament, Philip Gosse is opposed to the new theories of Charles Darwin, espoused here by biologist Brackley. Assuming "the Lord's will" determines the fate of his ailing son Edmund, Philip Gosse creates a life-threatening situation, even suggesting the illness is God's punishment because of Edmund's desire for a toy ship.