"The Princess Casamassima" is a novel by Henry James.
The novel is set in London in the 1880s in which different kinds of characters from all social classes are portrayed.
Hyacinth Robinson, an orphan boy, is the hero of the story. He has been brought up by Miss Pynsent, a quiet spinster who makes a living as a dressmaker. She lives in a lower-class district of London. Hyacinth hardly saw his mother, perhaps just once, and this is in prison. The meeting is depressed and sad because her mother is dying, condemned for the murder of his father, 'Lord Frederick.'
Hyacinth is apprenticed to the book-binder Eustache Poupin, a French Communist in exile. While he is learning the ropes of the trade in bookbinding he meets a proletarian revolutionary by the name of Paul Muniment. He joins a secret society becoming active to the movement. In the society, he comes into contact with Christina, the Princess Casamassima, who, being separated from her Italian husband, finds the revolutionary movement a good respite for her energies.
Hyacinth Robinson decides to travel to Europe when Miss Pynsent dies.
Somehow, his travel changes the way he sees the world around him and most importantly, he has a change of heart about the movement. He finds himself no longer supportive and committed of it. Despite his distancing from the movement, he still receives a summon to carry out the assassination of a duke.
Princess Casamassima plans to offer herself as a substitute for him and decides to go to his apartment. When she arrives, Hyacinth Robinson has already killed himself.