Tabbin sends you to Karnor's Castle to find three items: a drum, a mandolin, and a performance mask.
The Mask is a small chest drop from trash mobs; sentries and elites hav eboth been known to drop it.
The Mandolin drops from an iksar entertainer in the mess hall, which is at {{Eq2 loc|-143, -55, 180. the entertainer has a five minute respawn.
The Drum can be found in Commander's Quarters inside of a chest. Make sure you have show illusions ON in your Persona window, and be prepared for a fight when you click the chest.
Click the chest at -189, -41, 53 . As soon as you click it, a group of three advisors will spawn and attack you.
Click on the painting at -189, -41, 89 , across the room from the chest.
Click the chest again once you have killed the advisors in order to get the update.
If you have chosen to hide illusions, this step will bug and you will not get the drum from the chest when you click on it the second time. If you get bugged you need to camp and relog to fix it.
Return to Tabbin Juniper. He'll give you The Maiden of Masks, Incomplete. Unfortunately, he has torn out all the pages and used them as IOU's to pay his tabs at different bars across Norrath. Go find all the pages. Examine them like a collection to assemble the book.
Speak to Goldie Sams at Omen's Call in Fens of Nathsar. It turns out Tabbin owes her 185 platinum and 2 copper. Thankfully she lets you pay off the debt by bringing her more fish meat.
Kill 100 Yha-lei for auto-updates. There are plenty of fishmen in the ruins south of Omen's Call.