Planet of the Apes 5 movie series is a great example on how to make the ‘story’ interesting across sequels. The first movie is largely based on the novel “Planet of the Apes” by french writer Pierre Boulle. But for for the sequels, screenwriters employ concepts like time travel, apocalypse and nicely weave in the contemporary issues into screenplay, to make an outlandish theme ring true. A must watch for all the sci-fi fans.
In 2001, Planet of the Apes was selected for preservation in the United States National Film Registry by the Library of Congress as being “culturally, historically, or aesthetically significant”- Source Wikipedia