Mr. Smith is a middle-class Englishman who lives a comfortable, mundane life in the suburbs. He wears English spectacles and a small gray mustache. During his evening routine, he sits in his designated armchair, clicking his tongue and silently reading while his wife talks. He represents traditional bourgeois etiquette but easily slips into argumentative, contradictory conversations about trivial facts.

Mrs. Smith is an Englishwoman fully invested in her comfortable domestic life in London. She chatters continuously about basic facts her husband already knows, including what they ate and where they live. She frets over teaching her children good morals and acts as the primary enforcer of social niceties during dinner parties, though her own logic frequently contradicts itself.

Donald Martin is an English gentleman who recently traveled second-class from Manchester to London. He lives in a fifth-floor apartment on Bromfield Street. He suffers from a profound lack of certainty and acts highly embarrassed in social settings. He relies on deductive reasoning to piece together basic facts about his own life and relationships.

Elizabeth Martin is an Englishwoman who recently moved to London. She shares a bed, an apartment, and a travel history with Mr. Martin, though she requires a long conversation to realize they are a couple. She frequently experiences mysterious embarrassment that makes conversation with her hosts difficult, often relying on bizarre anecdotes to fill the silence.

Mary is the Smiths' maid. She occupies a lower social class and is frequently scolded by her employers for her bold behavior. Despite her status, she is observant and holds secret knowledge about the guests. She attempts to step outside her assigned societal role by reciting poetry and engaging with the dinner party.

The Fire Chief is a public servant tasked with extinguishing all fires in London. He wears a uniform and views emergencies strictly as business opportunities, often expressing disappointment when there are no fires to put out. He charms the middle-class couples with his authority and his willingness to share strange moral fables from his personal experience.