Intercepting the Legion's Plans

Our scout Skara writes in the missive that she learned of a major Legion initiative. She was after two encoded orders held by Legion troops near us to get the details and this must be when she was killed. The Legion splits their messages into encoded parts so that we cannot read them. Skara also writes that her partner Brae, a codebreaker, was slain trying to reach our lines with a code book that we will need to translate the Legion's orders. It is vital you find the orders and that code book!