Proceed with caution, you must! There are TFA spoilers ahead.

If you've seen "Star Wars: The Force Awakens," you've probably left with a few questions.

One question that has been puzzling viewers is what plan of Darth Vader's Kylo Ren, the new bad guy, is trying to carry out. Throughout the movie Ren frequently expresses his desire to be as evil as his grandfather, Darth Vader, and he seems to idolize the dark lord — even though Darth Vader (spoiler alert!) turned good at the end of Episode VI.

At the end of "Return of the Jedi," Vader showed he wasn't all dark. When Emperor Palpatine attempts to kill Luke Skywalker, Vader intervenes to save his son's life and is fatally wounded. Vader's final line to Skywalker is, "tell your sister, you were right" (referring to Princess Leia), indicating Vader still had a good side and died at peace with himself.

So, does Kylo Ren simply not know what went down among Luke, the emperor, and Vader? Or is he aware and just idolizes the dark side of his grandpa?

The movie may not have answered those questions, but the book adaptation of the movie, which Disney/Lucasfilm had to sign off on before it was published, is more conclusive.

In the film's novelization, written by Alan Dean Foster, it is revealed that both Kylo Ren and Supreme Leader Snoke know the truth about what happened between Palpatine and Vader on the Death Star. Snoke also reveals that he has been around long enough to see the rise and fall of the Empire.

When the two discuss what occurred, Ren blames it on "sentiment." Snoke replies: "Such a foolish error of judgment. A momentary lapse in an otherwise exemplary life."

He continues: "Had Lord Vader not succumbed to emotion at the crucial moment — had the father killed the son — the Empire would have prevailed. And there would be no threat of Skywalker's return today."

Ren says he won't have the same problem, claiming that he is "immune to the light."

But Ren later proves that he faces the same struggle when he expresses doubts over killing his father, Han Solo. But ultimately he does kill Solo, perhaps because he knew the path his grandfather had chosen and actively did not want to make the same "weak" decision.