Warrior-monks with laser swords wander a gorgeous fantasy world modeled on ancient Japan, righting wrongs and pursuing a shadowy evil. It turns out they're a remnant population seeded by aliens millennia ago, and are now being manipulated by a different alien race who has the goal of bringing them into a greater galactic society. ...Um, occasionally a British guy shows up in a blue box and helps out.

In a double twist, it is revealed that the entire thing is a giant virtual reality game, and the audience is left wondering which of the characters are humans and which are computer programs, and if it even makes a difference.

(Star Wars, Okami, GURPS Space and GURPS Transhuman Space, The Culture, three guesses on the blue box one :P, Ghost in the Shell)