After speaking with Baron Urtamark you head out to find the cave he was talking about. You'll find the cave just east of Kufferath Castle.
Enter the cave and defeat any Unholy Crusaders and any cows carrying explosives.
Really?, you're using some poor cows to blow up the wall? Unfortunately you will have to kill them too. Something about killing innocent animals makes your blood boil and you're determined to see the end of the Crusade. You exit the cave and go to find Officer Willybald. Walk due north and you'll see the officer with his elite soldiers. Introduce yourself to finish this part of the chain quest.
You have news from the Baron? let's hear it then, but make it quick! We're running out of time.