An episode in a series that serves as a sequel to a previous episode. Different from a Two Part Episode, in that there may be several episodes (if not several years) inbetween the first episode and the one that picks up the plot again. Obviously this only applies to series where Stand Alone Episodes occur somewhat regularly. If the whole show is one long Story Arc, there's not enough seperating the plot of one episode from another to make labelling it a "sequel" meaningful. However, if a series has multiple Story Arcs, it is possible for a later Story Arc to be a sequel to an earlier one.