In Sawmill you will meet a spirit of Paladin Everhart.
During the conversation, he will ask you for the head of Mummy Dearest. If you agree, you will have to kill it and take its head. The fight will be difficult, especially on lower levels. The Mummy has attacks that allow it to easily knock down your whole team if they're too close to each other.
Note: don't eat the head. Just don't eat the mummy's head, for god's sake.
After the fight, talk to the Paladin again, he will ask you to take the head to Paladin Hardwin and then disappear. Hardwin is at the Palladin's Bridge. Talk to him to get the reward.
Reward: 4175 experience points + Gold + War-Owl Whistle