This is a GMing technique that can work wonders in many games. Make sure you have stuff happening in the background, that the players don't know about, but that intersects with what they're doing. NPCs have goals and plans too, and are running around doing things independently of the PCs, except for where their paths happen to cross.

If you do this well, you can create an immersive world where all actions have consequences beyond what the PCs immediately learn, but which remain consistent with the actions of NPCs and can be revealed later. If you do it really well, you can spring something like this on your players, where basically everything they did in the entire adventure to date turns out to be at cross purposes to what they should actually have been doing. Just imagine the look on their faces when you reveal a back story like this.

Transcript

Darth Maul: {voiceover} "All I could do was tail you to Coruscant."
Palpatine: The Jedi are with the Council now; did you catch up with them?
Darth Maul: ... I wasn't able to talk with them, no. Why do you want them involved, anyway? They're loose cannons.
Palpatine: We need the Jedi Council on-side. I'll have a word with them.
Darth Maul: Talk is cheap.
Palpatine: Fine, have it your way. I need you back on Naboo anyway; find out what the Trade Federation are up to.
Darth Maul: {voiceover} "I figured the Feds might yak if they thought they could buy me out."
{scene showing Feds and Maul saying something amusing}
Darth Maul: I know what Palpatine is up to, if you can cough up a better offer.
Nute Gunray: Oh rearry.
Darth Maul: {voiceover} "But they didn't bite."
Nute Gunray: {to hologram of Palpatine} Senator Parrpatine.
Palpatine: What do you want, you slimy snake?
Nute Gunray: Frattery will get you nowhere. It seems your choice in spies is getting worse. I scarcely berieved it possible.
Darth Maul: Seems they don't trust turncoats. Go figure.
Palpatine: If you kill him—
Nute Gunray: That would be a waste of both of our times.
Darth Maul: {voiceover} "Their arrogance got the better of them. It gave me the chance to contact my source and learn about the plan to blow up the moon and destroy the Gungans."
Darth Maul: {non-flashback} Which they've done now, and all because you meddling Jedi got in my way again.
Qui-Gon: Well don't look at me. Queen Armadillo was in command!