Star Wars: Rogue One Trailer - 13 Major Plot Hints
11. There's Going To Be A Jailbreak

The most intriguing part of the opening voice-over that establishes Jyn's crimes is that they aren't crimes against the Rebellion: the explicit mention of forging Imperial documents makes it obvious that at some point, Jyn spent some time at the Emperor's pleasure.
So, that poses a pretty pertinent question: are the Rebellion going to single Jyn out as a special target (they do seem to know an awful lot about her) and have to spring her out of Imperial custody?
Looking at the shot from the trailer that sees her shackled in the Rebel base, it doesn't look like she's actually under arrest, despite the handcuffs. She's not being forced to walk with her single "guard", she's not resisting (even when she has previous) and she's not taking the many opportunities to escape that are very obvious.

So could the handcuffs belong to the Empire? Is this shot immediately after a jail-break sequence? Could that be how she initially meets Diego Luna's character?