Case № INHER-01Yorkshire, October 1927
An Inheritance of Murder
British India, 1930s. A fishing-fleet romance, an inheritance that shouldn't exist, and a burnt journal rescued from the fire.
The case
An Inheritance of Murder
The box-one journal is hand-singed at the edges — its owner pulled it from the fire at the last second, and the heat still lingers on the pages. Lay out the spices, the cigarette cards, the letters and the boarding pass, and start working out who wanted her dead. A gentle entry point to the Cosykiller catalogue, built for first-time sleuths.
Sir Henry Ashcroft had not been liked. He had been respected — for his business, for his collection of Roman coins, for his standing in the county — but respect had never quite warmed into affection, even among the people who owed him money. Of whom, it turned out, there were rather a lot.
He was found in his study on the first night of the weekend, slumped over the desk where he had, hours earlier, summoned his solicitor on a matter he refused to discuss over the telephone. The brandy was untouched. The fire had been banked. The dogs had not barked.
The butler found him at half-past six. The doctor arrived at seven. By half-past eight the constable had spoken to everyone in the house and decided, quite against his brief, that the death was suspicious. It took the detective from London three days to arrive. It took the constable three hours to start making notes.
The case file
Everything the constable wrote, took, noticed, or quietly kept back — it’s all in the box. You won’t find the detective’s report. He never filed one. The case was closed as natural causes, the family moved on, and the house went to the wrong person, and then for eighty years no one looked at any of this, and then the house was sold and the new owner called us.
How it plays
A cosy evening of it, or a lingering afternoon. Three hundred and sixty minutes of reading, cross-referencing and the occasional small pleasure of realising that Uncle Robert has been lying about where he was at ten past seven. When you know who did it, check the final envelope.
The envelope contents
What's in the box
We do our best to theme the contents to the story. This means the box will include interesting objects like photographs, maps and other memorabilia. Most of the narrative part of the story is contained in different paper documents which include personal letters, household ledgers, telegrams, newspaper clippings and more.
- № 01
Ashcroft's final will
Two versions, notarised a week apart, with the solicitor's marginalia.
-
№ 02Guest statements
Handwritten depositions from seven weekend guests and the butler.
- № 03
The household ledger
Five years of accounts, staff wages and a single large payment that was never explained.
- № 04
Photographs
The weekend's informal snapshots and two stiff studio portraits.
- № 05
A bundle of correspondence
Letters from a London address. Receipts from a Knightsbridge jeweller. A telegram.
- № 06
The constable's notes
What he saw, and what he decided — against guidance — not to mention to the detective.
- № 07
Trace evidence
A shirt button. A fragment of burnt paper. A pressed glove.
Audience & difficulty
Challenging but solveable.
1927–1930s
Our games are designed to be challenging but solveable. This is our gentlest entry point — a cosy country-house mystery where the work is cross-referencing statements, spotting inconsistencies and following the paper trail. Light ciphering and no prior experience required.
Ciphers you'll meet
- Letter substitution
- Cross-reference puzzles
- Handwriting analysis
From the case
A closer look
Letters of praise
What detectives are saying
“I received my first box in mid December and have only just sat down to start reading — but I can already get a sense of fantastic attention to detail, from the turmeric pages to the chai tea to the book cover and the faded bits. Can't wait to begin to make sense of it all.”
“I'm a little over halfway through and I love it. The storyline is intriguing and draws you in deeper and deeper. The story is told through a journal, letters and drawings — and there are many physical clues along the way. Putting it all together to come up with theories and answers is very challenging, and every connection made gives you a sense of satisfaction. CosyKiller has made it to the top of my list.”
“I recently completed "An Inheritance of Murder" and I am officially in awe of the folks at Cosy Killer. The storyline was intriguing and the materials in each box were elaborate and contributed to the aura of mystery. The puzzles, clues and ciphers were varied and complex — and if you get stuck there's a community of nice folks to brainstorm with.”
Ready?Case № INHER-01
Post me a killing.
Other cases
More on the shelf
Case № HUMAN-01Classic
Valley of the Kings, Egypt, 1920s
The Curse of Humanrah
A cursed dig in the Valley of the Kings. One archaeologist dead, another vanished, and a funerary text nobody should have opened.
Case № SITEQ-01Classic
Mexico, 1953 · reopened 1973
The Secret of Site Q
An archaeological expedition. A member missing. A black market awakening twenty years too late.
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 Curse of Humanrah is the next step up with knock codes, Vigenère and occasional folding. The Secret of Site Q sits in the middle — challenging but solvable. The Legend of Ching Shih and Murder at Marlborough House are our advanced cases — do them 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. A note of caution: Murder at Marlborough House is set in 1888 Whitechapel and contains graphic descriptions and period drug references — 18+ for that one.
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, photographs, ciphers, maps and personal effects collected during the investigation. Some cases include dried botanicals, spices, telegrams, theatre programmes and small physical objects. Each case is a complete story in a single box, with the final solution sealed inside. Nothing to download or sign into.
How long does it take to solve a case?
Between six and eleven hours, depending on the case, the number of players, and how much you like to re-read. 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?
Each case comes with three sealed hint envelopes — open them in order when you get stuck. There's also an online community where other detectives swap ideas (link included with your order). If you'd rather not break a seal, 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.