In the Name of Honor
(Star Trek The Original Series)
by Dayton Ward (2002)

Captain Kirk ventures into the depths of a remote jungle planet to save hostages held by the Klingon Empire.

While well written, this does suffer from a lack of action and a lot of Klingon politics. It lumbers on to an ending where Kirk (in his best American accent) moralizes to the Klingons.

It feels like it could easily be an episode in the original series.