Star Wars: Rogue One - Predicting The Entire Plot In 10 Steps

Saw's information leads the quintet to a secret Imperial base hidden inside a rocky canyon (the rock structure does appear to be the same planet as Jedha, but that may not be the case) which they, and a small squadron of X-Wings, attempt to infiltrate at night. They go with a brute-force option, with Jyn and Cassian sneaking in while Baze provides cover (as evidenced from the second trailer and the sizzle reel).

There's no suggestion why they're here, but the most logical in terms of the set-up is that this is where Galen Erso is being held and they need to hear from him what the heck that Jedha-destroying weapon is. They find Galen, now a captive forced to work on the superweapon remorseful about the destruction his scientific exploration has wrought ("Now I am become death, the destroyer of galaxies"), who willingly gives up key details about how to stop his creation. Jyn is desperate to free him, but during the escape her father's killed, providing the ultimate motivation for what's to come.

On the way they meet Bodhi Rook (Riz Ahmed's character, whose minimal appearance in trailers points to a later introduction), a commercial pilot contracted to the Imperials who, witnessing the horrors that are being created here, chooses to jump ship and join the team bringing his former employers down.