Travel in the Halocline Pits

A group of three get transported to the Nightlight Zone after one buys a submarine with lottery winnings. As they try to figure out how to escape, they interact with a band of Cave Stalkers, who themselves are trying to escape a Watcher that has come down to the seabed. The three in the submarine are soon able to learn a vast array of knowledge about the realm, just so they can escape the Watcher.