To begin this quest, you need to speak with Sam and Max who can be found in Bowerstone Old Town. Accept the quest, and then run up the road to Bowerstone Cemetery.
On arrival a counter will appear in the bottom right hand corner of the screen indicating the presence of 100 hollow men. Follow the gold dust through the cemetery area and kill all the hollow men at each location that they appear until the number is reduced to zero.
Once you have exterminated the zombie threat, pick up the Normanomicon which it is located inside a tomb to the left at the top of the first set of stairs behind the giant expression statue in the large cemetery area.
After picking it up, return it to Max and Sam to reap your reward.