Come Into My Parlour is the fifth of seven volumes incorporating all the principal events which occurred between September 1939, and May 1945, covering the activities of Gregory Sallust, one of the most famous Secret Agents ever created in fiction about the Second World War.

Much of the action of the story takes place inside the Soviet Union, commencing with Russia entering the war against Nazi Germany. There to counter Gregory's plans is his arch-enemy, Gruppenfuhrer Grauber, as anxious as ever to settle the long-standing score which has existed between them, and as plot and counter-plot carry the story to a Swiss lakeside villa, the final scenes are played out in a sinister castle situated deep in the heart of a German forest.