The Black Prince is the story of London author Bradley Pearson's affair with rival and friend Arnold Baffin's daughter, Julian. The affair ends in disaster and in Arnold's murder at Bradley's hands. The narrative then progresses into a postscript in which the characters themselves reflect on the novel. The novel's name is an allusion to Hamlet, which is itself featured prominently during the course of the novel and discussed at length by the characters.
The Black Prince is remarkable for the structure of its narrative, consisting of a central story bookended by forewords and post-scripts by characters within it. It largely consists of the description of a period in the later life of the main character, ageing London author Bradley Pearson, during which time he falls in love with the daughter of a friend and literary rival, Arnold Baffin. For years Bradley has had a tense but strong relationship with Arnold, regarding himself as having 'discovered' the younger writer. The tension is ostensibly over Bradley's distaste for Arnold's lack of proper literary credentials, though later the other characters claim this to be a matter of jealousy or the product of an Oedipus complex. Their closeness is made apparent from the start of the book, however, as Arnold telephones Bradley, worried that he has killed his wife, Rachel, in a domestic row. Bradley attends with his former brother-in-law, Francis Marloe, in tow. Together they calm the injured Rachel and restore peace to the Baffins' household.
Yet Bradley begins to get trapped in a growing dynamic of family, friends, and associates who collectively seem to thwart his attempts at achieving the isolation he feels necessary to create his 'masterpiece'. His intervention in the Baffins' marriage, for instance, prompts Rachel to fall in love with him. His depressed sister, Priscilla, leaves her abusive husband, demanding that her brother shelter her. The Baffins' young daughter, Julian, declares her admiration for Bradley and begs him to tutor her. Even Christian, Bradley's ex-wife, invades his life by seeking to repair their long-defunct relationship.
Bradley attempts to navigate these complications with mixed success. His inability to reciprocate Rachel's affections ultimately defuses their affair. She agrees, much to Bradley's satisfaction, to be no more than his friend. Christian meanwhile starts an affair with Arnold, drawing her attentions away from Bradley. Indeed, Arnold informs Bradley that he intends to leave Rachel for Christian. Yet Bradley fails to give proper attention to Priscilla, who pathetically alternates between despair and hysterical optimism. Only Francis remains a constant annoyance; the former psychoanalyst is implicitly in love with Bradley.
During this time, however, Bradley cannot escape falling in love with Julian. He privately vows never to confess or seek to realise this love, but he cannot contain himself. He promptly blurts it out to Julian herself, and the two embark on a brief, intense affair. He steals away Julian to a rented sea-side cottage to evade Rachel and Arnold, who both condemn the relationship. But he also neglects pressing needs at home. Priscilla, left without any companions, commits suicide; Bradley nonetheless postpones returning. He feels that the news would destroy any romantic connection between him and Julian. When Arnold arrives, enraged, to collect his daughter, however, he turns this deception against Bradley. Julian is visibly disturbed, and she promises to return home the next day. Yet Julian vanishes in the night—in Bradley's mind, at least, Arnold has taken her off and hidden her against her will.
Bradley returns to London in a lovesick fury. A jealous Rachel confronts him, (incorrectly) telling him that Arnold has taken Julian to Europe. She mocks Bradley's high-minded notions regarding love; Julian, she says, already rues their affair. Filled with anger, Bradley tells Rachel about Arnold's plan to leave her. This revelation startles Rachel and she departs. The final action of the main section takes place at the Baffins' residence, where Bradley attends an incident parallel to the opening one. Rachel appears to have struck Arnold with a poker, killing him. Taking pity on her, Bradley helps her clean up the crime scene and advises her to tell the police the truth. She instead blames the murder on Bradley; he is put under arrest.
Bradley's arrest, trial, and conviction for Arnold's murder are briefly described. The police attribute the murder to Bradley's jealousy of Arnold's writerly success. No one can corroborate Bradley's version of events; Francis's obviously biased account only harms his cause. Thus, his affairs with both Rachel and Julian, as well as Arnold's affair with Christian, remain secret. Rachel appears as a grieving widow, whereas Bradley appears as a cruel, possibly homosexual sociopath. He is convicted and sent to prison. Bradley then closes his account from his prison cell, reaffirming his love for Julian.
This section is told from the point of view of the other characters, each being said to have had the luxury of reading the main section before drafting their responses. Each interprets the action differently, focusing on separate issues to a more or less selfish degree. They exist to cast doubt not only on the veracity of the fiction that preceded it, but also on themselves. Christian, for example, dismisses any accusation of self-interest, claiming that Bradley lied because he was still in love with her. Francis assesses Bradley as a dysfunctional neurotic to promote his new book. Rachel also claims that Bradley may have lied due to unrequited love. Julian herself has little to say: she states that she remembers little of that time, and that she has no wish to remember anything more. The "editor" of the entire volume concludes the novel by supporting Bradley's account and praising his devotion to love as an all-empowering force.