Within the French secret service operates a clandestine branch of undercover agents. Dispatched to key locations all around the world and living under false identities for years at a time, their mission is to seek out and identify potential sources. In order to fulfill their mission, their false identities must be totally undetectable and highly elaborate. These fabricated identities are called "legends". Creating them takes months of work, maintaining them takes discipline. All this and more lies deep in the heart of the most confidential branch of the secret service: The Bureau.