Clarissa Dalloway, elegant and vivacious, is preparing for a party when her old suitor, Peter Walsh, arrives unannounced and reveals that he is still in love with her.

Clarissa invites him to the party as he leaves and wonders whether she will now start to doubt her relationship with her husband.

In another part of London, Septimus Warren Smith is shell-shocked and on the brink of madness.

Smith's day interweaves with that of Clarissa and her friends, their lives converging as the party reaches its glittering climax.

Past, present and future are brought together on a momentous June day in 1923.