Also called a Midquel, this is, quite simply, when a new entry in a series is a sequel to one existing entry, and aPrequel to another, or alternatively takes place during aTime Skip in an earlier entry rather than continuing the story. This device is often used to expand a portion of the story only touched upon in other entries, or if more story is desired but there's no logical place for it either before the beginning or after the end. Happensa lot inVideo Games, since story has only recently become a major part of design. A more cynical creator might use it to cash in on a franchise without having to advance theStory Arc.Not that we want to name names, or anything...
ComparePrequel,POV Sequel.