Preface: Wodehouse sets the scene in a version of New York where real gangs and commercial murders exist; his tale, he says, is rooted in actual incidents.

Summary:
Cosy Moments is a painfully domestic weekly, guided in the proprietor’s absence by the anxious, chirpy editor J. Fillken Wilberfloss and carried on by a thin-paid sub‑editor, Billy Windsor, a tough young ex‑rancher dreaming of a city journalism career. When Wilberfloss is ordered to take ten weeks’ complete rest, Billy—sullen in his “caged‑eagle” way—assumes greater charge. Into the office stride a pair of English visitors: the laconic Mike (a cricketer) and the fastidious, witty Psmith, who quickly deems the paper a target for radical overhaul.

Psmith and Billy engineer a sensational re‑launch: Cosy Moments is transformed from nursery small‑talk into a red‑hot weekly that champions the public, exposes abuses, and even runs a sporting column backing Kid Brady, a plucky Wyoming pugilist. Their lead crusade is an expose of rotten tenement housing on “Pleasant Street.” The campaign enrages powerful interests; emissaries and hired gangsters begin to menace the paper. Psmith, unflappable and inventive, proposes practical countermeasures—surveillance, bribed information, and recruiting muscular protectors.

The office acquires an improbable guard: Bat Jarvis, Bowery animal‑dealer and Groome Street gang leader, and his silent lieutenant Long Otto; Kid Brady becomes the paper’s unpaid “fighting‑editor,” ready to intercept roughs at the door. Episodes of slapstick violence follow—rooftop sieges, pistol ambushes, a street brawl in which the Kid and Billy rout assailants, and an attempt to buy off the editors by a sleek emissary, Francis Parker. Parker kidnaps Psmith in a taxi, intending darker work later, but Psmith’s cool and a fortuitous tyre blowout bring the Kid to the rescue; Parker is felled.

The campaign’s pivotal piece of evidence—an original rent‑collector’s slip naming the owner of the tenements, Stewart Waring—comes into Psmith’s hands after a clever pickpocketing. Psmith, who reveals that he has actually acquired the paper during the upheaval, confronts Waring. Rather than prosecute, the editor‑proprietor negotiates: Waring pays to make the tenements decent (and Psmith cheekily demands three dollars for a ruined hat). The immediate threat evaporates; Bat Jarvis’s friendship discourages further gang action.

Resolution: the tenements are to be improved, the election ambitions of Waring are thwarted, Kid Brady’s boxing career advances, Billy is temporarily jailed but survives his ordeals, and Psmith returns to Cambridge with the quiet satisfaction of a journalist‑proprietor who has made New York “sit up.” The story closes with Psmith contentedly considering the “Cosy Moments” successes from afar.