This is a humorous story concerning a civil servant, Silas Oak, working for the MOP (Ministry of Protection) who is given the task of finding a departmental mole who is leaking classified information to the London Press. Suspects include Len Hoppit, the office messenger; Dougal O'Leary, an Irishman; Girlie Lush, a secretary; and Boris Karpov, a fervent trade unionist. The trail of the mole takes Silas to Fleet Street, where he meets Sam Squiggle, the always hungry, ever-thirsty reporter for the Daily Record, to a seance where a contact is attempted to a passed-over suspect, to a dinner party where he is mistaken for a conjurer, to a theatrical costumier where he is fitted with a disguise, and on a frantic chase around Sainsbury's. Eventually, by chance, the mole is identified and Silas gains an uneasy promotion.