Last Men in London follows an Englishman named Paul, from childhood through service with an ambulance crew in the First World War (mirroring Stapledon's own personal history) to adult life. Olaf Stapledon's previous science-fiction novel, Last and First Men, envisioned two billion years of history, from the 1930s forward. In this companion piece, a super-intelligent narrator from the remote future investigates 20th-century life, entering Paul's mind to observe his childhood, his service during World War I, and his life afterward.