The star portals are dead. Ship City is dying.

But there is still hope.

You are Explorers in a dangerous world. You do the work few others will. The enigmatic ruins of the Great Dark are shunned by most, but not by you. You seek them out, to delve into their shadowy depths and uncover their secrets. The Blight – the cataclysmic scourge that spreads from the ruins – is your beacon. Where there is Blight, there are artifacts to find and mysteries to solve. Ship City is fading, but you and your fellow Explorers can find a way to a better future.

So don your delver suit, step aboard a mighty Greatship and venture down the Slipstream towards the unknown. Your creed: explore or perish!

Inspired by 19th century expeditions, deep sea diving and pulp archaeology, Coriolis: The Great Dark is a roleplaying game about exploration and intrigue. Join dangerous expeditions, navigate the Byzantine schemes of Ship City, and hunt for the keys that unlock the mystery of this Lost Horizon.

This beautifully illustrated 308-page hardback book features:

Rules for creating your crew of Explorers, with upgrades such as talents, vehicles, and crew maneuvers to enhance campaign play.
Rules for delving into the unknown, traveling on Greatships through the dangerous Slipstream, and trekking across wild planets.
A detailed gazetteer of the Lost Horizon, the eleven systems of the Charted Sphere and the asteroid-metropolis of Ship City.
The Black Ziggurat, an introductory adventure that will take you deep into an ancient ruin on a distant moon.
Tools and rules for solo play, making it possible to explore the Lost Horizon all by yourself.


It may not be possible to ship very heavy items outside of the Mainland UK.
Released: 15 October 2025