Returning to the Sea: A Deep Dive into Call of Cthulhu's Innsmouth

Today, we’re talking to Chaosium’s Call of Cthulhu creative director Mike Mason about Innsmouth, the latest expansion for the popular horror TTRPG. Based on the classic Lovecraft story, the book expands on the lore around a Pennsylvania town where its residents find their fates increasingly intertwined with eldritch fish-like entities from beneath the waves.

Originally published in 1931, The Shadow over Innsmouth is a serialized novella by H.P. Lovecraft about an investigation into Innsmouth, a town in Massachusetts that had developed a superstitious reputation. As the main character dives deeper, he finds that it’s a town where many residents join the Esoteric Order of Dagon and worship the Deep Ones, ancient eldritch creatures of the past. Some are even breeding with them, creating Hybrids. The practice has gone on so long that many of the residents have taken on fish-like traits, including scales and gills. Some of the residents even go on to become Deep Ones themselves. The main character soon has to fight to escape. The town is later investigated and quarantined by the U.S. government, while the protagonist slowly learns that he might have Deep One blood as well.

The original story has acted as a touchstone in Lovecraftian fiction, inspiring films, novels, video games, and more. It’s arguably among one of the best-known stories in Lovecraft’s collection.

It only makes sense, then, to want to explore Innsmouth in your own Call of Cthulhu game.

 Chaosium’s Innsmouth is a sandbox resource that offers tools for exploring every nook and cranny of the Massachusetts town, according to Chaosium creative director Mike Mason. It was written as a follow-up to Arkham, a 2024 volume designed to let players explore the region of Arkham and all the eldritch chaos the iconic town had attracted over the years. It’s part of an ongoing series of supplements designed to help tables explore the Miskatonic Valley (a fictitious region made up of Arkham, Innsmouth, Dunwich and other named locations in Lovecraft’s work)

The Innsmouth writers took a more “prescriptive” approach to storytelling with the sandbox setting, Mason told TTRPG Insider, a notable contrast from the more directed approach that Call of Cthulhu scenarios usually take. The story hooks in Innsmouth are “designed to be very flexible, with a number of ways to enter them, and a number of different ways you could reach a climax in the story,” Mason said. Each district of Innsmouth holds its own breadcrumbs and hooks for a well-trained Keeper to use. Those plot hooks are also designed to fit a variety of playstyles (detectives versus academics versus ‘ghostbusters’, etc.), so players have a number of reasons to get nosey about the town.

There is also a wide spectrum of story hooks available. While players might go into Innsmouth expecting to discover Deep Ones and Hybrids, Mason notes that the game has plenty of non-Deep One story hooks woven through the city. Lovecraft’s The Thing on the Doorstep, for example, features an antagonist from Innsmouth.

A Keeper could easily tell a longer story that’s only based in Innsmouth, Mason said, or they could also intertwine the tale with Arkham. There are a number of references between the books that could be used to have players interact with both settings.

Making Innsmouth Your Own Fishy Haven

One unique element of the Innsmouth resource is its flexibility regarding the facts of Lovecraft’s original Shadow over Innsmouth. How do you tell a story about Innsmouth without walking in and assuming you know the details of your table’s tale because you read the original author?

Assume the story is wrong, Mason said. “If you actually read the story closely, the narrator of Shadow over Innsmouth is potentially an unreliable narrator,” he said. “So none of it could have happened, or part of it could have happened, or he could have imagined it all up. That leaves it completely flexible for you to play the version of Innsmouth you want to play and the story that you want to tell.”

For example, the original novella assumes that the Deep Ones are inherently malicious. A CoC Keeper could run a story where this remains true. It’s also possible that the Deep Ones want to help humanity, or are pacifistic and just want to be left alone. Maybe they just want to protect the Earth from humanity’s history of stealing resources. The book outlines a number of ideas for how the setting's monsters could be run.

Changing up the facts of the story can help “reinvigorate the story with new ideas, and free up your table to retell a fiction story the way you want,” Mason added.

You can check out Call of Cthulhu: Innsmouth on DrivethruRPG or their store.

Disclosure: A review copy of Innsmouth was provided to TTRPG Insider.

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While I’m sure you’re mostly here for Chaosium content, I also published a preview of the latest D&D release on Monday that might be of interest. Arcana Unleashed offers new depth to D&D’s magic, while the Deadfall adventure offers a high-level magical spy thriller set in the land of Thay.

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