Martin Lynch-Gibbon's marriage comes apart
Martin, a complacent London wine merchant with a secret young mistress, Georgie, is told by his wife Antonia that she is leaving him for her psychoanalyst, his friend Palmer Anderson. The couple insist on staying affectionately close to Martin. The fallout then works through nearly every pairing among six people: Martin finds Palmer in bed with his half-sister Honor Klein, learns that Antonia has long been sleeping with Martin's brother Alexander, and sees Georgie become engaged to Alexander and attempt suicide. In the end Antonia goes to Alexander, Palmer leaves for America with Georgie, and Martin is left facing Honor, the one person he cannot manage.
