Jake's work for MI5 appears to be in jeopardy, and his friend Griff, who works with MI6, supports him as they connect with a young couple from the Crimea who want to alert Britain to some of Russia's recent subterfuge-they think there's a Russian mole deep in British Intelligence. At first, it looks like they'll be able to unravel the mystery...until Jake's boss Hubert vanishes, along with his Russian-born wife. Griff now finds himself juggling a missing MI5 official along with a potential case of terrorism, brought to his attention by a young Iraqi refugee who wants revenge against the extremist who murdered his mother.

Jake's wife, Kate, a police officer with Scotland Yard, provides a connection to DCI Charlie Knowles, and he works with Griff and the young refugee to foil an ISIS plot on British soil, while Griff and Jake have to take on another task when Hubert and his wife reappear, with the news that a high-level asset in Russian intelligence wants to defect.

Multiple storylines collide in Wry Treason, showcasing the complicated nature of intelligence work in the twenty-first century.