READ the cover image you posted. The title doesn't match. Gotham Knight is not a part of Batman: The Animated Series. However Bruce Timm was on production and Kevin Conroy voices Batman (both vets of the series). The special edition does offer a few episodes of the series picked by Timm as filler.

This film is set in the film universe (kind of) between Batman Begins and The Dark Knight. There are, of course, no major revelations or any sort of plot progression that would be missed between the two. What the 6 interlocking stories offer is mostly deeper insight into Batman/Bruce. It starts off a bit slow, but gets successively better throughout. Easily the best of the new crop of DC animated films, but doesn't have a whole lot to do with the whole TV theme we're aiming for here.