June, 1917. While another daylight air raid batters London, the body of respected businessman Gilbert Donohoe is fished from the Thames. Inspector Marmion struggles with the murder case alongside his anxieties for his now-missing son, Paul, but the pressure increases when the Metropolitan Police are the target of a series of vicious press attacks. As Marmion is pilloried in the press, he uncovers a seedy path through London which will lead him towards the killer.