What type of plot structure allows authors to follow different characters through their own separate narratives, eventually converging, as the story is resolved?

episodic plot structure
parallel plot structure
in medias res
flash-forward

In media res is when a character is dropped in the middle of action, and that being the beginning of the story.  A flash forward is something that is shown in the story out of chronological order, usually for dramatic effect or irony. Episodic plot structures are much like TV show episodes, following a rising action-climax -rising action-climax pattern. I believe the answer you are looking for is Parallel Plot Structure. :)

Well where is the passage!