A narrative device used by many television series shows to bring the viewer up to date with the current events and plots. It is usually a short (between 20 to 40 seconds) montage of important scenes that set up the following episode, so that viewers who had not seen the previous episode or who do not remember what happened on the previous episode can understand from where the current episode will pick up. They usually begin with a voiceover proclaiming, "Previously on..."