Rogue: Section 31 (Star Trek: The Next Generation Book 2)

They are the self-appointed protectors of the Federation. Amoral, shrouded in secrecy, 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.
Six months before their ultimate battle against the Borg for the fate of Earth, Captain Jean-Luc Piccard and the crew of the USS Enterpriseâ„¢ face a very different kind of crisis. A world in turmoil becomes the focal point of conspiracies and betrayal as an unexpected reunion brings with it startling revelations. Old friends become bitter enemies and one young officer reaches a crossroad when he's forced to choose between the greater good of the Federation and the ideals for which it stands.
NO LAW. NO CONSCIENCE. NO STOPPING THEM.