When old Mr. Dashwood dies, the estate is tied up for a distant grandchild, and a deathbed promise to provide for his half-sisters is whittled away by their brother and his calculating wife until almost nothing remains. Mrs. Dashwood and her three daughters are turned out of comfort into a small Devonshire cottage, genteel but poor. From the first pages the book fixes attention on money: who has it, who is denied it, and how that shapes what the sisters may hope for.
The two eldest embody the title. Elinor, nineteen, has strength of understanding and a coolness of judgment that let her govern feelings which are nonetheless real and strong. Marianne, younger, is clever and generous but eager in everything, prizing the intensity of her emotions and scorning prudence as a failure of soul. Their mother shares Marianne's temper, so it falls to Elinor to be the steadying counselor of the household.
Each sister meets a man. Elinor grows attached to the diffident Edward Ferrars, only to learn he is secretly and long engaged to the scheming Lucy Steele, who confides the fact to Elinor as a triumph. Marianne is swept up by the charming Willoughby, who courts her openly and then abandons her without explanation to marry for money. Elinor hides her own pain and keeps Lucy's secret for four months; Marianne broadcasts her anguish and collapses into it.
The contrast sharpens into crisis. Marianne's refusal to govern her grief, and her neglect of her own health, bring on a fever that nearly kills her. Recovering, she looks back with horror at a season of imprudence toward herself and unkindness to others, and resolves to regulate her feelings by reason, religion, and constant employment. Elinor, meanwhile, is released from her long silence when Edward, freed by Lucy's defection to his richer brother, is at last able to come to her.
The novel ends in marriages that reward steadiness. Elinor weds Edward on a modest income; Marianne, cured of her doctrine that a heart can love only once, comes in time to give her whole heart to the older, constant Colonel Brandon, the very kind of suitor she had once dismissed. Faithless Willoughby keeps his fortune and his regret. The settling of incomes and households is as much the book's resolution as the settling of hearts.