It continues from where the second season left of and tries to carry on in a similar style to the second season.
However the characters no longer develops, the new characters gets almost no screen time or development at all, new running gags comes up whilst old ones are either edited or removed.
At this point it is basically just staggering on and have lost most of its spark, if you have seen the second season sure watch this to conclude the series otherwise you really aren't missing anything.