Tell Me Lies, Tell me Sweet Little Lies – Part 2

Tell Me Lies, Tell me Sweet Little Lies

Converting Pelgrane’s ‘Eternal Lies’ Campaign to Call of Cthulhu

By Andrew Nicholson

Part Two: Where Angels Fear to Tread

So, the general concepts for the conversion were in place…next step was – how would I deal with the actual individual encounters? And how was I going to get it all done?

Spends and Skill Rolls

Trail uses a concept of spends to achieve something – how does that equate to Call of Cthulhu’s skill rolls ?

I read through the system conversion ideas in the back of the Trail of Cthulhu rulebook again. I sat down with a cup of tea, and gave it some thought.

I went back to my rule #1: Preserve the flavour. 

You need to have the skill to succeed to able to do a spend. Tasks requiring larger spends were more difficult. This is simulated in Call of Cthulhu by modifying the investigator’s skill rolls.

So, I split the spends into a couple of categories – regular spends and bigger spends. Regular spends would become an ordinary check against a skill, and bigger spends would halve the investigator’s effective skill for the roll. This seemed to work pretty well in play-testing.

Ok, so that’s it for spends…but what skills should they be rolling against.

Many skill conversions were pretty easy – both systems have a Physics skill for example. However, there are some skills that don’t naturally match, and in some rare cases, identically named skills weren’t a perfect fit.

So…back to rule #1 again. Preserve the flavour.

This meant treating every skill use listed in the adventure had to be considered on a case-by-case basis. I looked at the context and situation of the check, and converted them to whatever seemed to be the most suitable existing skill or mechanic. On a couple of occasions I had to invent new ones, particularly in regards to some spells.

There will be no doubt some occasions where the Keeper may disagree with the answer I came up with – but that’s great. The game, after all, is yours – I view the work as “a” conversion rather than “the” conversion, based on my interpretation of the authors’ work – something to help Keepers run the game, but not restrict them…and if you think something else fits better, that’s great, go with it. I guarantee I will not send a Hunting Horror around.

However, by having to list every skill check in this way, the document got long, very long. Plus, the idea was to write conversion notes; something for a Keeper to use as a reference when they get to a point where a game mechanic is mentioned in the Eternal Lies book – not to replace the book entirely.

As a result, reading the conversion in isolation may seem a bit odd. I definitely recommend you read through the relevant chapter of Eternal Lies first before reading any of the matching conversion chapters. The good news is that we have split the conversion up into matching chapters so that you can more easily reference each section . -and not have download and print it out all at once!

Thugs and Monsters and Ghoulies, oh my.

Converting the statistics of the various characters the investigators meet – and especially their combat skills – was always going to be a bit of a challenge. The two systems have very little in common mechanically here, but fortunately BRP and Call of Cthulhu have a large back library of critters to help out.

The bigger creatures were stated first, and saw a fair amount of play-testing to make sure they posed a suitable level of threat.

The trickiest thing to convert, in the end, was actually the low level dangers – the various thugs and ne’er-do-wells. In Trail of Cthulhu these sordid types are often specified with low health (hit points) , but to do this in Call of Cthulhu would mean generating disbelief-destroying low constitutions. Not only that, but often the weapons they were equipped with could be far more deadly in Call of Cthulhu than they are in Trail.

In the end, a compromise was necessary. The thugs were given lowish but believable stats, but their skills and equipment were often adjusted downwards. For a few rare encounters, even with this reduction there was no way to both preserve the narrative flavour and level of challenge, especially as Call of Cthulhu groups vary so wildly in combat abilities.

In the end, I opted to preserve the narrative flavour for these tricky encounters, but to also flag those encounters to the Keeper so they would know to give it some extra consideration.

Converting the pre-generated characters also required a compromise. As I had suggested several ways to approach core clues, the effectiveness of a given skill level could potentially vary. In the end, I went for what seemed to be a fair average, and it seemed to work okay.

I’m Going Slightly Mad…

Sanity Loss was another thing to consider. In any long horror campaign, it’s a given the players should deteriorate in well-being over time, but if you lose too many characters to insanity and death too often then the campaign will lose its coherence.

I also feel that some sanity losses as defined in the Call of Cthulhu rulebook can be random – the difference between getting 1 and 20 on a D20 sanity loss is massively game affecting. There is also the wide variety of SANs the Call of Cthulhu adventurer can have –  a horrific encounter may have a worse effect on a 50 SAN character than an 80 SAN character, but again too wide an effect can be a problem.

As a result, when converting SAN losses, I tended to err on a slightly smaller die for SAN loss, but to make the minimum loss (even on a success) 1 point. That said, this is still a deadly campaign, and some encounters will blast your investigators minds. Much like combat skills, the difference between different investigator parties can be quite large, and the SAN losses are only suggestions – feel free to adjust them up or down based on their capabilities.


I could never match the amount of playtesting that was done on the original campaign, but I still needed to get it tested to a decent standard.

Playtesting a large campaign in a short time was going to be tricky. The only way was to convert the encounters in chunks, and test them a section at a time. Not only that, but the people I normally play Call of Cthulhu with were either not available, or wanted to play the campaign fully later on .

But still, I found some willing volunteers, and we tried out the various encounters and chapters – sometimes (albeit rarely) in entirely the wrong order – to make sure the conversion was working reasonably. Sometimes a rewrite was required or a tweak made, meaning it had to be tested again.  I also spent many hours playing with.. err.. by… myself to test out the rules before waving at my volunteers.

Then we went back to try to ensure the conversion hung together as a logical whole.

Notes were written. Reams of handwritten notes.

Type, Type, Type

Meanwhile I was busy typing up and editing those notes. I’d be working on converting one chapter while typing up another. A couple of times I had to remind myself what chapter I was working on today…hang on, have they done X yet? Do I need to put in the stats for Y, or can I refer to a previous chapter?

Then I had to proof read it, and pass it onto a volunteer proof-reader. Edits, re-edits. In the meantime I was also looking for a real-life job and running two weekly RPG campaigns. I was, to say the least, very busy.

I typed the chapters up in the same order as they appear in the Eternal Lies book, both to try to make sure I wasn’t missing everything, but also to make it easier on my poor printer. It also meant I could keep Pelgrane clearly informed on my progress, which (seeing as it was my first work for them) made me feel a lot more secure. I must say they have been very supportive, which has helped make this considerably easier.

Eventually…the closing act

At last, we came to the final chapter and the final act. Exhaustion had begin to creep in and I was making mistakes. I had to take a break. I put the notes away forgot about it for a week. Then, with one final effort….done.

Relief washed over me…to be replaced seconds later with worry. Would people like it? Would there be burning torches and pitchforks outside my door?

I had seen the wave of reactions, good and bad, when Call of Cthulhu 7th edition was announced and, well…I’m sure it won’t polarise folks anywhere near as much as that. Still, it’s an unnerving moment to know its going to be made available to the public. Pleasing…but unnerving. I hope you all find it useful.

So, that’s it, that was how I went about creating a conversion for Eternal Lies.  I hope you found the discussion of the process valuable. As I’ve mentioned, I don’t consider my work “the” definitive conversion, merely “a” conversion to help Keepers to run the campaign their way. I hope that it provides many hours of happy gaming.

Finally, my thanks to all at Pelgrane letting me do this, the numerous family and friends who offered support throughout the process, and to Will, Jeff and Jeremy for writing the original campaign. May your printers never run dry.

And now, dear reader…It Falls To You.

Good luck. The world is counting on you.

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