On a beautiful morning in 1923, Clarissa Dalloway sets out from her large house in Westminster to choose the flowers for a party she is holding that evening. Her teenage daughter Elizabeth is unsympathetic, preferring the company of the evangelical Miss Kilman. A passionate old suitor, Peter Walsh, turns up and does not disguise the mess he has made of his career and his love life. For Clarissa this confirms her choice in preferring the unexciting but affectionate and dependable Richard Dalloway. At her party Sally turns up, who was her closest friend, so close they kissed on the lips, but is now wife of a self-made millionnaire and mother of five.
Intercut with Clarissa’s present and past is the story of another couple. Septimus was a decorated officer in the First World War but is now collapsing under the strain of delayed shell-shock, in which he is paralysed by horrific flashbacks and consumed with guilt over the death of his closest comrade. His wife Rezia tries to get him psychiatric help but the doctors she consults are little use: when one commits him to a mental hospital, he jumps from a window to his death. The doctor turns up late at Clarissa’s party, apologising because he had to attend to a patient’s suicide. Clarissa stands by a window and ponders what it would mean to jump.