"Scattered bits and pieces of the Episode 1 plot line have popped up in various places in cyber space. But to this very day, the meat, the bones and the very heart of the Episode 1 script has been successfully kept hidden from would-be prequel spies. However, it doesn't take an expert in microbiology, nuclear physics or the pan flute to figure out with reasonable certainty what the "main thrust" of the prequel story line is going to be.
The key to shining some light on this question is to analyze George Lucas's prior Star Wars movies. Specifically, you need to study the similarities between the plot structures that appear in the original trilogy . . . In SW: A New Hope, a worn-out Jedi Master named Obi-Wan enlists the help of a Jedi-wannabe, Luke Skywalker, to deliver the droids and the death star plans to Bail Organa on Alderaan. However, the story turns to the real plot line when Alderaan is destroyed and these warriors along with Han and Chewie are captured by the Empire. The real crux of the story now revolves around rescuing the fair maiden in distress, Princess Leia. Hence, this is the first time that George uses the "rescue somebody" plot line in a Star Wars film.
The "rescue somebody" plot premise also appears in the "sequel" to Star Wars. In the Empire Strikes Back, George and co-scriptwriter, Lawrence Kasden, again have Luke on a rescue mission. Just as in the first film, Luke has to rescue the fair maiden in distress, Leia, and this time additionally his other friends from Lord Vader. Just as in SW: A New Hope, this rescue by Luke turns out to be a trap Lord Vader sets to capture Luke just as the rescue from the death star was a trap set by Vader so that Han, Leia and Luke would lead the Empire to the Rebellion's secret hidden base. Then George twists the "rescue" plot line to make it seem fresh, original and it becomes ironic when the would-be hero, Luke, becomes the "fair maiden in distress" (so to speak) who has to be rescued from the bottom of Bespin by Leia, who Luke thought he was going to rescue!
Subsequently, in Return of the Jedi, George and Lawrence Kasden once again use the "rescue somebody" plot line at the beginning and end of this movie. Once again, Luke Skywalker is out to rescue somebody. This time he is out to rescue his dear friend, Han Solo, from Jabba the Hutt. And once again, George twists this "rescue" plot line to make it different.
While Lord Vader was unable to capture the elusive Luke as part of his trap, Jabba does successfully capture Luke, which is a part of Luke's plan to destroy Jabba if Jabba will not free his friends. This time Luke ends up saving himself and the other heroes with the use of his Jedi skills.
Using this plot line once in ROTJ is not enough for George this time. He uses it again at the end of ROTJ. Luke sets out to rescue his father, Lord Vader, from the Emperor. It seems that in George's mind that one of the Jedi Knights primary functions galactic rescuers, who save family, friends and others who come into distress or imprisonment. Once again George twists this plot line to make appear new and different and just like in the ESB where Luke thought mistakenly thought he was going to rescue his friends from Vader, he is wrong about his ability to rescue his father by himself. Once again, a family member has to rescue Luke from peril. This time Vader rescues Luke from the Emperor and the destiny of both Luke and Anakin is forefilled.
Now let's examine the Prequel Trilogy. In Episode 1, George has stated that we finally get to see the Jedi Knights doing what Jedi are suppose to do and that function is to act as a "police" force that upholds law, order and justice all throughout the Old Republic. George has also stated that the prequels are going to be more epic in scope than the original trilogy. What does this mean? Well, instead of having a small group of people (i.e., Luke) rescuing a small number of people (i.e., Leia, Han and his friends); George is obviusly going to have a bunch of light sabre wielding Jedi Knights rescue a very large group of people, who are held in bondage by the bad guys. George again twists the cliche "rescue" plot device to make it new, exciting and original. While Luke and Co. rescued the fair maiden in distress in SW: A New Hope, Obi-Wan and Co. rescue the fair maiden in distress' family, friends and kingdom in Episode 1. This gives the rescue a much more epic and broader scope, giving the George the opportunity to show many Jedi Knights in battle during the rescue mission.
Then, undoubtedly in Episode 2 when the Clone Wars appear, Anakin, Obi-Wan, Bail Organa and others will be some how involved with "rescue(s)" involving the new bad guys of Episode 2 possibly the Mandalorian super commmandos. George could possibly once again twist the "rescue somebody" plot line into the "rescue something" plot line. Instead of rescuing people, maybe the Jedi Knights have to "rescue" cloning technology, the Kyburr Chrystal or Jedi holocrons from the Madalorians, Sith Lords or whoever George chooses to be the bad guys. Or perhaps, it would be more accurate to call this the "race against evil" plot line that George used in each of the Indiana Jones movies. In each on the Indy flicks, Indiana had to "race against the bad guys" to recover some valuable artificat whether it be the Lost Ark, the jewel-embedded stones or the Holy Grail. It seems logical that the control of cloning technology will be important to the outcome of the Clone Wars. Hence, maybe the Jedi Knights have to "race against the bad guys" to keep cloning technology out of the hands of evil or to "rescue "IT" from the bad guys who possess it. The fate of the galaxy rests in the balance with the Jedi Knights succeeding in Episode 2.
Then, in Episode 3 at least one more "rescue" attempt occurs which parallels Luke's attempted "rescue" of Vader from the Emperor. In Episode 3, Obi-Wan unsuccessfully tries to rescue Anakin from the clutches of the dark side and Palpatine. However, once again George twists this "rescue" plot device by having Obi-Wan's rescue attempt fail quite miserably. Even worse, Obi-Wan and Anakin duel and as a result of falling into the molten pit during their light sabre duel, Anakin becomes the mechanical monster called Darth Vader. This is the same basic plot device as George used in ROTJ with completely opposite results because Obi-Wan fails to bring Anakin back to the light side of the Force in Episode 3.
However, while we may be able to guestimate that different kinds of rescue plot lines will be used in the Prequel Trilogy. We can have no idea of what kind of twists and turns George will use to make these cliched plot devices seem like something that we haven't seen before. Also, there are many other subplots (i.e., Palpatine's rise to power, Fett's role in Ep 2, the courtship/marriage/break up of Anakin and the Queen, etc.) that George has planned that we will continually be surprised by the storyline . . . "