Proof of Integrity
DISCLAIMER: Your Steps and Tasks may be different
You will need atleast neutral Mau of Bastet faction to be given this quest.
1)You have to speak to him to get the quest. He's very long-winded, so be prepared to spend several minutes reading through all he has to say. Eventually, if you agree to show proof of your integrity, he'll give you the quest.
2) You have to kill and bring back to him 20 setian ears as proof of your integrity towards the maubastets. The only setians I was able to get the ears from were Setian Scouts and Setian Warriors, all near the Setian Bandit camp around 3k, 17k in Stygian Delta. (Ears can also be collected from Laborers in Atun 63600 15100 at the camp there.)
3)After you get 20 setian ears, an information window pops up and tells you that you've gained 20 setian ears and you should return to Pedibastet.
4)When you return, you have to give him the 20 ears. But be aware that he won't take them stacked. You have to hand them to him 1 at a time. Once you've given him all 20 ears, he'll give you a Golden Tuning Fork.
Pedibastet's final words:
The Golden Tuning Fork is used to find the Stone of Atlantis when searching for that artifact. Once the Keeper of the Stone is killed, you use the Golden Tuning Fork to locate the stone itself.