This ist from the 6th mission of Star Trek Legacy. The Objective is to find this Vessel and capture it to learn mor about the new Cloaking Technology. It is said, that the Cloaking Device is so advanced, that even Klingons cannot penetrate it.
(actually i still wonder, how these stupid warrior race could ever develop such advanced technologies. blood and honor is the only important thing for klingons, they barely have doctors and scientists have a bad reputation.)