Brought up in poverty, Hyacinth has nevertheless developed aesthetic
tastes that heighten his awareness of the sordid misery around him. He
is drawn into the secret world of revolutionary politics and, in a
moment of fervour, makes a vow that he will assassinate a major
political figure. Soon after this he meets the beautiful Princess
Casamassima. Captivated by her world of wealth and nobility, art and
beauty, Hyacinth loses faith in radicalism, "the beastly cause." But
tormented by his belief in honor, he must face an agonizing, and
ultimately tragic, dilemma.