Star Trek: Section 31, book 01 : Cloak
S.D. Perry2001

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.

Once, in order to preserve the galaxy's fragile balance of power, Captain James T. Kirk carried out a dangerous mission to capture a cloaking device from the Romulan Star Empire. Months later, while investigating a mysterious disaster aboard a Federation starship, Kirk discovers that the same technology he obtained for the sake of peace is being put to sinister purposes. What the crew of the Enterprise uncovers will send shock waves through the quadrant, as Section 31 sets in motion a plan that could bring the major powers of the galaxy to their knees.