Awesomest campaign: The Two-Headed Serpent

Maybe not the best (tough competition with Masks and Eternal Lies). But the awesomest, for sure.

I’ve run The Two-Headed Serpent four times: three groups of four players, one of five. My tables have included a wide range of ages, professions, and nationalities, and the campaign always landed. That says something.

Sure, it says I am an awesome Game Master.

But, it also says something about The Two-headed Serpent.

This is, without exaggeration, the most entertaining Cthulhu campaign ever published. It’s fast, loud, dangerous, and absolutely bursting with action. Think Indiana Jones, The Mummy, and weird pulpy 1930s sci-fi filtered through Lovecraftian horror. It is not purist Lovecraftian horror, for sure. In fact, it is totally out there. And it is glorious. 

(Warning: light to medium spoilers ahead)

You’ve got ancient conspiracies, serpent folk riding dinosaurs, laser guns, high-speed chases, fights in planes out of control, crumbling temples, sci-fi fortresses, ancient gods and all-powerful AIs. 

Structure and Style

Each chapter is set in a different, vividly realised location—from steaming jungles to icy wastelands to seedy 1930s cities. The scenarios are varied and strong across the board; it’s hard to pick a favourite because the campaign thrives on variety. It’s structured mostly as a series of missions, but once the heroes are dropped into a location, the story flows naturally from their goals and survival instincts. No need to push them, they’ll charge forward on their own. Of forced to, to survive.

And like the first scenario, you may want to start others in media res, just for the Kicks.

The campaign gives players real choice in who to trust, who to side with, and even who the final villain is. While that final choice doesn’t dramatically alter the final structure, it’s enough to give the players a sense of ownership. Across four runs, I saw players approach problems in radically different ways, and the system handled it all smoothly.

One thing that helps: agree early on that your characters are pulp heroes. The story, and its moral dilemmas, works best when the players are committed to doing the right thing, even if the cost is high.

Prep and Presentation

If you’re like me and enjoy historically accurate detail, you’ll want to do some extra prep—but it’s not as demanding as Masks of Nyarlathotep. Locations in The Two-Headed Serpent are often used more as colourful backdrops than deeply lived-in settings. I recommend reading the book once through, then reviewing each chapter before you run it, and keeping notes on NPC agendas.

To enhance realism, I used real historical photos, watched 1930s travel footage on YouTube, and brought in pictures of places like Snake Island and Icelandic fishing villages. It made a big difference to immersion. For maps, I kept things simple—hand-drawn doodles on paper, which worked well, but you could run it with minis, VTTs, or whatever suits your group.

NPCs and Custom Additions

One of the few weak points in the official material is the underdevelopment of Rose and the rest of the non-Caduceus factions. To fix this, I added a custom scenario (made by me) in La Mosquitia, with a search of the site of the legendary City of the Monkey God. There, my players encountered a Tsathoggua temple guarded by three proto-Nazis twisted by Mythos power. Rose was also hunting for the temple, and that brief interaction gave her arc more emotional weight later on.

I also expanded Tyrannish significantly, especially in campaigns where PCs became hybrids. I wrote encounters where she argued for her vision of a merged serpent-human future. She wasn’t just a villain—she was an idealist and dreamer, and Calcutta became a morally charged flashpoint when players realised how many "eggs" she was willing to break to make her omelet.

Difficulty, Tone, and Pacing

This isn’t a brutal campaign, after all, it’s Pulp Cthulhu. But each of my runs ended with at least one dramatic final death, and players felt they had truly earned their endings. One group was rescued by Tyrannish (after saving her from a Shoggoth earlier), while others succeeded in convincing the citadel computer to self-destruct. That last ending, reached twice, was particularly satisfying.

The tonal balance is one of the campaign’s best qualities. It blends horror, action, exploration, and mystery, and my players loved the change of pace. The horror is real—including disturbing body horror and some tricky ethical choices—but it never kills the pulp fun.

Who Is It For?

I wouldn’t recommend The Two-Headed Serpent for brand-new Keepers. It’s fast, layered, and benefits from thoughtful improvisation. But for new players? Absolutely! Especially if you frame it as a high-energy pulp adventure. Just make sure to lean into both sides: the fun and the fear. A wacky ride can still have weight. And that starting scene is worth gold.

Final Verdict

The Two-Headed Serpent is what happens when you throw Lovecraft into a blender with serial adventure fiction and just enough moral ambiguity to keep things interesting. It’s a full-throttle, cinematic experience. If you want your players to explore ancient ruins, discover horrifying truths, and crash a plane into a volcano while being chased by nightgaunts, this is the campaign you’ve been waiting for.

Don’t run it like gothic horror. Run it like you’re standing on a burning dirigible, shooting at serpent folk with one hand and holding your fedora with the other. And turn up that pulp-o-meter.

Verdict: A genre-defining pulp epic. Don’t walk, run (maybe while being chased by a mind-controlled ape with a flamethrower).