From the Back of the Book:
Valachia's comrades are all dead and she is trapped in the belly of Aufstrag. Rescuing her would be an act for the very brave or very foolish. But the price she offers cannot be passed up. Gate in, find her, gate out.
That's all needs to be done, almost.
Where the dark is darkest.
User Note: This product was sent as a reward to some backers of the 7th printing Castles & Crusades Player's Handbook. It is not widely available at the time of this writing.