Book #12 of the Papa Pontivy series.
This is a flashback adventure showing a case Bernard Newman was involved in back in 1941 and the Second World War. An RAF officer is shot down and held in a POW camp. He holds classified intelligence much needed at HQ so Bernard Newman is ordered to break in, get it, and get out again. What he learns is the facts of Operation Barbarossa, a secret plan underway by the Germans. He and his friend, Papa Pontivy, decide to put a stop to it.