In 1818 England, the poet John Keats (BEN WHISHAW) is a struggling, penniless artist with no idea of his greatness. His most pressing concern is caring for his brother, Tom (OLLY ALEXANDER), who is dying from tuberculosis.
At the same time, he becomes smitten with his next-door neighborhood, Fanny Brawne (ABBIE CORNISH), a strong-willed seamstress who lives with her mother (KERRY FOX) and two younger siblings. The two are drawn to each other, despite the protests of Keats' friend and fellow poet, Charles Armitage Brown (PAUL SCHNEIDER), an arrogant, boorish man who wants Keats and his talent all to himself.
When Keats also falls ill to the same disease his brother had, his and Abbie's love is put to the test as he wrestles with the decision to leave England for a climate more conducive to his health.