The Traitor’s Code

by Stephen Ronson Book 4 in the John Cook series.

First published 2026

Amazon

2.5(5)

England, 1940. John Cook’s train is halted at gunpoint by men posing as Home Guard officers, and two of them escape into the woods carrying mysterious suitcases. At the same time, Lady Margaret is helping place members of the Women’s Land Army on local farms when one of the new recruits is found dead, raising the possibility that an enemy operation has penetrated their own community.

Cook and Margaret’s investigations begin to converge around refugee scientists from occupied Europe and secret work on a weapon that could alter the course of the war. As false identities, coded information and divided loyalties accumulate, the pair must determine whether the danger comes from German agents, a British traitor or someone closer still. The fourth John Cook novel keeps its focus on the concealed war being fought across Britain’s home front.