The brave and the bold - Keith R. A. DeCandido

Two of the four Malkus artifacts - deadly weapons lost millennia ago - have been found since their existence was discovered by Captain Jonathan Archer in 2151. Two more lie in wait, ready to wreak havoc on an unsuspecting galaxy. . .
On their shakedown cruise, Captain Kathryn Janeway and her crew discover the third artifact in the Demilitarized Zone -- but the weapon is in the hands of the Maquis. Security chief Lt Tuvok must infiltrate the Maquis and gain the trust of cell leaders Chakotay and Cal Hudson, before the renegades use the artifact to cause chaos throughout the DMZ.
Meanwhile the final artifact is unearthed on Narendra III, leading to the disappearance of two of the Federation's most respected Ambassadors, the Vulcan Spock and the Klingon Worf. Captain Jean-Luc Picard of the USS Enterprise joins forces with Captain Klang of the IKS Gorkon -- but even the strength of these great vessels combined may not be enough to save them when the deadly secret of the fourth artifact is revealed.