You see a group of adventurers gathering by the sea shore. They look well equipped for a journey. No four legged transport is near them.
They approach a small open boat and climb aboard.
As they leave Grand Harbor of Nalo Island, they continue discussing what they will do.
For they are heading for The Tok, a series of reefs and an ocean deep, which is northeast of the island.
After several days travel they arrive. One rock juts out of the ocean higher than the rest. A small flat area is on top. They put their supplies there. As they are about to put in pitons and establish a camp on the side of the rock, they notice someone else has done the same thing before.
They look for magic, evil, animal, and stone creatures.
None are found, except down in the water.
As near as they can determine, the rock is a rock.
The small boat leaves and returns to harbor.
They get a night of rest. The supplies they will need after they return to the suface are left behind protected by more than the usual wards and protections.
A force sphere is created and they all climb inside.
A set of chairs and benches line the sides. Not uncomfortable, but not too comfy either.
They sphere moves away from the rock, then sinks into the water.
Expeditions have come here before and not returned.
This group has decided to make some changes. A book has told them to always have their magic light 50 feet in front of their sphere. They have decided to place it 75 feet to the lower left. And to make their sphere and contents invisible. Which the book cautions to not do. They have been unable to find the source of the book. A small mark found on the inside of the spine resulted in a year’s search of sages. The mark isn’t from any surface civilization known to any of the sages they talked to. Its possible it is from an aquatic group of people. Someone, according to the sage, appears to have written a good book of advice on underwater adventuring that appears to be helpful. Particularly for anyone who doesn’t do research ahead of time. The sage tells them the book is written in such away as to give misleading advice while appearing to be helpful. The sage has been on underwater adventures, and is a survivor of a group who realized the book gave bad advice.
Sadly they lost the other 2 spheres of people before realizing that.
The sage tells them to not just toss the book, nor should they randomly alter the advice. He gives them a copy of his book written after their return. He warns them to sell their other book, but not to be surprised if it reappears among their belongings. Such a thing has happened before.
Unknown to the sage or the party, there is a tracking spell on the book. The sea creatures who wrote the original, will know when the book is near the ocean.
One of the magic-users has decided to destroy the book before they get to an ocean. After he does so, the book, or a copy just like it, shows up in one of their packs.
After spending money for a Wish, it disappears and doesn’t return.
Several times one of them almost buys another copy at the market.
They resist the mild compulsion.