Many popular movies have sub-stories. Similarly, with DVD it is possible to have a multistory capability. For example, if the main character and a supporting character part in a movie and the storyline continues to focus on the main character, an episode about the supporting character can be inserted. Such an episode can be long or short, and once it's completed the action may, or may not, automatically resume the main storyline at the point where the main character and the supporting character meet up again.

So, when watching a movie involving several characters, you can first enjoy the main story by automatic playback, and on second viewing you can select a sub-story from the menu screen. It may be possible to select the whole movie from the beginning, or just the sub-story.