Antique Bookstore is owned by Ni Laoshan located in the Ghostlight Market area. Here’s the exact location on the map:
The quickest and easiest way to go there is to use the Ghostlight Market boundary stone (teleport) and walk straight until at the gigantic mask gate, and the Antique Bookstore will be there on your left.
Physical look of Antique Bookstore:
When you walk into the bookstore, you will see Ni Laoshan sitting upside down reading book on the ceiling:
Interact with him and choose “see what he’s selling…” to open his The Buried Tomes store.
Here you will find a bunch of books that you can buy, all of Ni Laoshan items are sold in Coin, so make sure you have a lot of coins before making any purchase.
Antique Bookstore is the first location that you come to if you want to unlock Sword Horizon inner way.
To get all x10 Sword Horizon: Page, you need to buy Unknown Old Book, it can cost you between 12500 coins to 300k coins.
Depending on your luck you might get it cheaper than me, but to be guaranteed you need to purchase all 30 Unknown Old Books.
Note: Always set the time to You hour before entering the Ghostlight Market area and avoid going there during Mao hour.
In short, if you’re planning on visiting Ni Loashan, always go during You hour, walk straight from the teleport stone, and look at the ceiling. You’ll find him there.
End.