Mexico and America 1950s-1980s
The Secret of Site Q
A body uncovered at an abandoned campsite in the dense Mexican rainforest reveals there was more to a simple tragedy.
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The case
Discover lost civilisations and spies as you pick your way through the dense multi-layered story.
The plot
The search for Site Q began in earnest in the 1970s when a Yale Graduate Student noticed a similarity between a number of artefacts and monuments in various collections that were of unknown origin. Purchased on the antiquities black market, these artefacts had to have come from the same source. A repeating snake head glyph and various other features, including some inscriptions which were continued across a variety of monuments held in different collections, prompted the search for what Scientists began calling "site Q". The letter itself standing for "¿qué?", Spanish for "which?"
Heavy looting of this mysterious site had clearly been going on for some time. With museums and private collectors paying significant sums for stelae, panels, sculptures and codex-style pottery. Tracking down the provenance of these illegally secured artefacts is still underway, but with Museums and Private collectors easily paying prices of $30,000 – $120,000 for the best preserved relics, few in the local communities are willing to give away their secrets.
This story starts back in the 1950s with an archaeological exploration into the dense forests surrounding the Usumacinta River, bordering Guatemala and Mexico.
An important ancient trade route, the river cuts through the rich Mayan Lowland, and travellers regularly report seeing hidden ruins lurking in the dark of the densely forested banks.
As the grandchild of one of the student anthropologists from the original expedition, it falls to you to piece together what happened and exactly who is responsible for the terrible fate that befell one of the team whose body remains buried somewhere deep in the dark and foreboding forest.
Join us as we explore the history of the first expedition and why Site Q was never found.
How it plays
This is the latest in our long form multi-episode cases and many would say it's our best. Designed to be solved over several sittings there are codes and ciphers that can be solved in every box as well as the longer form cross referencing our players love as you pick through the narrative to solve the cold case. Expect each episode to take round an hours with the full case needing between 9-12 hours to play through. Signposting is available in each box, with links to the detectives forum and the hints available on the inheritance hunter website for those who need to check results.
Designed for the curious
The Secret of the Site Q is one of our best longer form mysteries. Designed to be played over several sittings, each box is packed with material for you to explore. Substitution Ciphers, logic puzzles, knock codes, Caesar ciphers, Vigenère ciphers and letter exchange ciphers are included within this box, as well as some one time ciphers as the case moves into the modern period. This is the perfect gift for someone who loves adventure stories and is ready to take their case file mystery solving to the next level.
The envelope contents
What's in the box
We always theme the contents to the story. This case spans a period of time from the 1950s through to 1980s and beyond, so the box contains replica newspapers, magazines, postcards, photographs, military archives and numerous bundles of letters as the three friends correspond. Across the boxes there's a developing narrative between the three friends who formed bonds during the fated expedition.
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Replica newspapers and magazines
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Postcards
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Photographs
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Military archives
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Bundles of letters between the three friends
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Code-solutions notebook
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Sealed final solution envelope
Ciphers & cross-references
What you'll be working with.
1950s–1980s
Built for puzzle-lovers and experienced sleuths this case includes Morse, letter substitution ciphers, knock code, Caesar, Vigenère acrostics and secret messages. Not all codes are easily found, but all are signposted so you know where you should be looking and can check you've found them all before turning to the solution.
Ciphers you'll meet
- Morse
- Letter substitution
- Knock code
- Caesar
- Vigenère
- Acrostics
- Secret messages
Before you buy
Common questions
I'm new to Cosykiller — where should I start?
Start with An Inheritance of Murder. It's our gentlest case, built for puzzle-minded beginners — Braille, letter-to-symbol substitutions and one-time cipher pads. The Secret of Site Q is the step up: a longer, cross-referencing investigation that's challenging but solvable. Shadows in the Gallery is our most advanced case, layering Playfair, knock code and Caesar ciphers across a post-war art theft — do it once you've worked one of the others.
How old do you need to be to play?
Cosykiller is written mainly for adults, but families can participate together. Every case is rated 14+ for themes of murder, and Shadows in the Gallery touches on wartime violence and post-war trauma, so we'd steer younger players towards An Inheritance of Murder first.
What's inside a Cosykiller box?
It varies by case, but every box contains a cover letter from Fairhall & Brett Inheritance Recovery — the fictional investigators who brief you on the case — followed by the documents like photographs, ciphers, maps, letters, military archives, telegrams, postcards, and other personal effects collected during the investigation. Some cases include dried botanicals, spices, theatre programmes and small physical objects. Each case is a complete story, with the final solution provided at the end. Nothing to download or sign into.
How long does it take to solve a case?
2-4 hours for our single box solves, and between 6-11 hours for some of our longer games. Length of time also depends on the number of players, and how much you like to re-read and how quick you are at spotting and solving ciphers. Most people spread a case over two or three evenings. You can pause whenever you like — put the lid back on, come back next weekend. Nothing expires.
Can I play solo, or do I need a group?
Both work well. Every case is designed to be solvable on your own — no mechanic depends on a second reader. That said, two to four players is where a case shines, because half the fun is arguing civilly about motive over a drink.
I'm stuck on a code — what do I do?
If you become totally stuck on a code, check out the <a href="https://fairhallandbrett.co.uk/" target="_blank" rel="noopener noreferrer">inheritance hunter's website</a> or join the online community where other detectives swap ideas (link included with your order). If you need one on one help then email <a href="mailto:supersleuth@cosykiller.com">supersleuth@cosykiller.com</a> with your case number and the document you're stuck on and we'll help without spoiling things for you.
Ready?
Mail me the case.
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