Sealed Mystery
Blackfile №2: A Death at the Wyke Hydro
A speculator dies beside his nightcap in a snowbound spa hotel; the culprit was sealed before you play, and the AI cannot change the answer.
- Players
- 1
- Length
- 75–105m
- Ages
- 12+
- Version
- 2.0.0
- Updated
Works with ChatGPT · Claude · Gemini. Free, no signup.
Opens ChatGPT or Claude with the play prompt ready; press send if it hasn't started. Same link on your phone as on your desktop. Another app? Copy the play prompt into it, or, if it can't open links, copy the full game card below. What works where.
No web access, or want it as an installed app?
The game card is the entire game — every scene, rule and answer, about 13k characters. Paste it when your assistant can't browse the web. The Skill installs Blackfile №2: A Death at the Wyke Hydro into Claude on any plan: download it, then turn on code execution under Settings → Capabilities and add it at Customize → Skills → + → Upload a skill.
Blackfile №2: A Death at the Wyke Hydro is a free murder mystery you play inside ChatGPT, Claude, or Gemini. A snowbound 1929 poisoning whodunit: six suspects, one cup of hot milk, and an answer sealed before you start. Solo, 75–105m a run. No signup and no app — open it in your assistant, or paste the play prompt anywhere else.
How to start
- Open it in your AI. Tap Open in ChatGPT or Open in Claude, and press send, or paste the play prompt into any assistant that can open links. No paid plan required.
- The game loads. The case file includes the sealed hash and boots the Wyke Hydro on the night Gerald Vane died.
- Investigate. Question the six snowbound suspects, search the rooms, and follow the poison back from the cup.
- Accuse and verify. Name the poisoner, the poison, and the reason — then open the seal and hash it yourself.
Questions
- How do you stop the AI from inventing the murderer at the end?
- Who killed Vane, how, and why were written out and hashed with SHA-256 before the card shipped, and that hash is printed in the case file you paste. The AI can only reason from that fixed text — it cannot decide the answer is whoever you happen to suspect at hour two — and when you accuse, you can hash the reveal yourself and watch it match.
- Is the case actually solvable, or is it guesswork?
- It is solvable by deduction. Every clue the answer rests on can be found in the house, and each innocent suspect is cleared on at least two independent grounds. Find the evidence, test what it really shows, and the answer is fixed.
- Do I need dice, an account, or any tools?
- No dice — this case turns on deduction, not rolls — and no account beyond the chat app you already use. Paste the case file into ChatGPT, Claude, or Gemini and the Hydro opens on the night Vane died. Checking the seal afterwards takes the free checker at aigamecards.com/verify, which runs in your browser.
- How long is it, and can I stop partway?
- About seventy-five minutes if you go straight at it, closer to two hours if you question everyone. Say "save" at any point to print a save code, then paste it into a fresh chat with the case file to resume exactly where you left off.
- How is this different from Blackfile №1?
- Different house, different crime, different shape of proof. №1 is a disappearance from a bolted conservatory in a 1925 country house, with no body and no way out; №2 is a poisoning in a 1929 spa hotel, with six suspects the blizzard has shut in and a cup of hot milk at the centre of it. Play them in either order — they share nothing but the seal.
- Has this case changed since it was released?
- Once. On 28 September 2026 Blackfile №2 was re-sealed as a second edition (v2.0.0) with a new solution, after a reader's letter showed that the first edition gave itself away once the cause of death was known. An answer never changes within an edition. The first edition's seal (v1.1.0) still verifies: choose it at /verify and paste the reveal you were given.
12+ — a poisoning, and a reference to a suicide in the backstory.