 The underlying concept of the series is that the reader is a member of an agency known as Spy Center, an organisation that maintains order throughout the galaxy and falls partway between a police service and an intelligence agency.This agency has its headquarters in Sector 666, known as 'The Sector of Illusions'.The reader's character is usually referred to simply as Spy, and the story and illustrations almost always deliberately avoid identifying the Spy's gender or any specific physical characteristics, ensuring the widest possible chance of affinity between the Spy as character and the reader.