The Dalloway house is in chaos; both the usual household staff and additional workers hired for the party are eager to please their hostess and ensure everything runs smoothly. Among the staff is  Mrs. Walker, the cook, who feels the most pressure, knowing that she is cooking for the Prime Minister, who is rumored to attend the event.

Mr. Wilkins introduces each guest as they enter the party. Nearly every name he reads off is a notable member of London society. Despite the immensity of her staff and their careful preparations, Clarissa is convinced that the event will be a failure. Overcome with anxiety, she questions herself about why she is even hosting the party. In response, she argues that it is far more preferable to take a chance and live fully than to wither away and disappear.

Clarissa observes Peter as he enters but chooses not to acknowledge him. Peter's ability to cause her to reflect on herself makes her uncomfortable, particularly in the current moment. Ellie Henderson is by herself and seems amiable but despondent, and when Richard takes pity on her, she feels thankful. Later on, when Peter greets Richard, the two of them engage in a comfortable conversation, despite their history.

Gradually, the house fills, as more and more people arrive. The soft hum of conversation and the steady stream of new arrival comforts Clarissa, who thinks about how hosting parties allows her to break free from her usual self by observing and engaging with others differently.

Mr. Wilkins announces Lady Rosseter, but Clarissa is not familiar with the name. However, upon realizing that Lady Rosseter is actually Sally Seton, Clarissa becomes ecstatic. Her excitement is fleeting, however, as Clarissa notices that Sally no longer possesses the same unique qualities and characteristics that she once attracted her. 

As Clarissa mourns her friend, who has changed so much, Mr. Wilkins announces the Prime Minister. Shaken from her thoughts, Clarissa jumps into action and begins to introduce him to everyone personally.  The atmosphere becomes more subdued as the attendees show their respect for his presence; despite his unremarkable appearance, the man has a significant impact on the guests.

Peter Walsh observes with disdain as he watches Hugh speak with Lady Bruton. The stilted pleasantries of their conversation only reinforce his belief that the social scene is filled with hypocrisy. Lady Bruton expresses her gratitude to Hugh for helping her with the letter and explains that she wishes to bring it up to the Prime Minister, but the Prime Minister departs shortly after, and she is unable to.  Sally greets Peter, and they engage in conversation, but Clarissa is unable to join them in reminiscing because of her duties as a hostess. Memories of Bourton swim to the surface, a past that continues to haunt their thoughts.