When the episode begins, Geordi is aboard a shuttle craft--bound for some R&R on Raisa and then a conference. However, en route, his shuttle is taken by the Romulans. For some time, he undergoes brainwashing techniques to turn him into an unwilling and unknowing assassin. All this coincides with some sensitive negotiations with the Klingons. It seems some of their people are blaming the Federation for interfering with one of their colonies--claiming they are providing rebels with weapons. Who LaForge will kill and what's next is something you'll need to see for yourself.
All in all, this is a rather exciting episode--as just about all the Klingon episodes are exciting. Additionally, the ending is sweet and makes the show well worth seeing.