From the back of the book:
In Roche asteroid field, a secred Rebel project nears completion. Headed by Commander Ackbar and staffed by insectoid aliens, this procect - code named Shantipole - will provide powerful new starfighters for the Rebel arsenal.
First though Shantipole must be safely escorted back to the Rebellion. That's where you and your team come in. With sealed holo-disk orders and a good blaster at your side, your ship emerges from hyperspace - right into the middle of a TIE fighter patrol!
And they told you this was going to be a routine mission ...