Section 31.

"Historian's Note. The main narrative of this story takes place in late 2386."

"Amoral, shrouded in secrecy, and answerable to no one, Section 31 is the mysterious covert operations division of Starfleet, a rogue shadow group committed to safeguarding the Federation at any cost. The discovery of a two-hundred-year-old secret gives Doctor Julian Bashir his best chance yet to expose and destroy the illegal spy organization. But his foes won't go down without a fight, and his mission to protect the Federation might end up triggering its destruction. Only one thing is for certain: this time, the price of victory will be paid with Bashir's dearest blood." --