A recap sequence (or recap, often announced as "Previously on...") is a narrative device used by many television series to bring the viewer up to date with the current events of the stories' plot. It is usually a short (between 20 and 40 seconds) montage of important scenes cut directly from previous episodes, usually short bursts of dialogue, which serve to lay the background for the following episode. On the NBC show ER, main cast members rotate turns saying the phrase "Previously on ER..." which is then followed by scenes from previous episodes which are pertinent to the current episode.