In 1818 Hampstead, the fashionable Fanny Brawne (Abbie Cornish) is introduced to poet John Keats (Ben Whishaw) through the Dilke family. The Dilkes occupy one half of a double house, with Charles Brown (Paul Schneider) occupying the other half. Brown is Keats’ friend, roommate, and associate in writing.
Fanny’s flirtatious personality contrasts with Keats’ notably more aloof nature. She begins to pursue him after her siblings Samuel and Toots obtain his book of poetry “Endymion”. Her efforts to interact with the poet are fruitless until he witnesses her grief for the loss of his brother Tom. Keats begins to open up to her advances while spending Christmas with the Brawne family. He begins giving her poetry lessons, and it becomes apparent that their attraction is mutual. Fanny is nevertheless troubled by his reluctance to pursue her, for which her mother (Kerry Fox) surmises, “Mr. Keats knows he cannot like you, he has no living and no income.”
It is only after Fanny receives a valentine from Brown that Keats passionately confronts them and asks if they are lovers. Brown sent the valentine in jest, but he warns Keats that Fanny is a mere flirt playing a game. Fanny is hurt by Brown’s accusations and by Keats’ lack of faith in her; she ends their lessons and leaves. The Dilkes move to Westminster in the spring, leaving the Brawne family their half of the house and six months rent. Fanny and Keats then resume their interaction and fall deeply in love. The relationship comes to an abrupt end when Brown departs with Keats for his summer rental, where Keats may earn some money. Fanny is heartbroken, though she is comforted by Keats’ love letters. When the men return in the autumn, Fanny’s mother voices her concern that Fanny’s attachment to the poet will hinder her from being courted. Fanny and Keats secretly become engaged.
Keats contracts tuberculosis the following winter. He spends several weeks recovering until spring. His friends collect funds so that he may spend the next winter in Italy, where the climate is warmer. After Brown impregnates a maid and is unable to accompany him, Keats manages to find residence in London for the summer, and is later taken in by the Brawne family following an attack of his illness. When his book sells with moderate success, Fanny’s mother gives him her blessing to marry Fanny once he returns from Italy. The night before he leaves, he and Fanny say their tearful goodbyes in privacy. Keats dies in Italy the following February of complications from his illness, just as his brother Tom did earlier in the film.
In the last moments of the film, Fanny cuts her hair in an act of mourning, dons black attire, and walks the snowy paths that Keats had walked many times. It is there that she recites the love sonnet that he had written for her called “Bright Star” as she grieves the death of her lover.