Here is an overview of the game, via its Steam page:

About

Captain your fishing trawler to explore a collection of remote isles, and their surrounding depths, to see what lies below. Sell your catch to the locals and complete quests to learn more about each area’s troubled past. Outfit your boat with better equipment to trawl deep-sea trenches and navigate to far-off lands, but keep an eye on the time. You might not like what finds you in the dark…

• Explore the Islands and Discover their Secrets – Starting from your new home in the remote archipelago, “The Marrows,” take to the water and scour the depths for curious collectables and over 125 deep sea denizens. Explore each area while completing quests and visiting neighboring island regions—each with their own unique opportunities, inhabitants, and secrets.
• Dredge the Depths – Someone wants you to dig up the past, but can you trust them and will it ever be enough?
• Beware the Fog – Danger is everywhere, so watch for sharp rocks and shallow reefs, though the biggest threats of all lurk within the fog that cloaks the night-time seas…

Key Features

• Unravel a Mystery – Captain your fishing trawler across a collection of remote islands, each with its own inhabitants to meet, wildlife to discover, and stories to unearth.
• Dredge the Depths – Scour the sea for hidden treasures and complete quests to gain access to strange new abilities
• Study Your Craft – Research special equipment and upgrade your boat’s capabilities to gain access to rare fish and valuable deep-sea curios.
• Fish to Survive – Sell your discoveries to the locals to learn more about each area, and upgrade your boat to reach even more secluded locations.
• Fight the Unfathomable – Strengthen your mind and use your abilities to survive trips out on the water after dark.

Watch a new trailer below.

Release Date Trailer