The world is still facing the threat of Islamist terrorism and with Russia also emerging as a new super power, the MI5 team face even more frightening and deadly challenges. Six months on from their terrifying ordeal at the hands of the Red Backs, Adam is back on the Grid but there is no sign of Jo. There's a new Spook on the block when a secret assignation between MI5 and the Russian intelligence services (the FSB) brings Harry's old protégé Lucas North back into the fold after eight years languishing in a Russian prison. Harry is- thrilled to have him back but does Lucas have the necessary skills to rejoin MI5 at the top level? And more importantly after eight years with only a high ranking Russian spymaster for company, can Lucas's loyalty really be taken for granted...?