We Made a Murder Mystery Game: Meet Guilty Party
A detective evening for four to six people, with no host to appoint and nobody knocked out halfway through. Here is what we built and why.
Hidden Agenda came out of a simple observation: the games that work at a party are the ones that do not interrupt it. You do not want to clear the table, deal cards and explain rules to someone who arrived ten minutes ago. So we built a game that runs underneath the evening instead of stopping it.
Then we kept running into a different evening — the one where people do want to sit down. Where the point is not background play but a story everyone is inside of for an hour. And every time we went looking for something to play on those nights, we hit the same wall twice.
The two things that were always wrong
Murder mystery kits are wonderful when they work. A period case, a table of suspects, everyone in character. The trouble is what it costs to get there. Somebody has to be the host: read the material a week early, assign roles, brief people on costumes, chase the two guests who have not confirmed. And the whole structure is brittle — when someone cancels on the day, the plot has a hole in it, because the script assumed they would be there.
We watched that happen. The host spends the evening administering the game rather than playing it, and if two people drop out, the box does not work at all.
Mafia has the opposite problem. It costs nothing — a deck of cards and seven people. But it asks two things that get worse every year. Someone has to narrate, which means one person is not playing. And the first person killed spends the next forty minutes on their phone. There is also no story to be inside of — you are in a living room saying “I think it’s Dave.”
So: one option that needs a week of preparation and a committed host, and another that needs neither but leaves people sitting out of their own evening. We wanted the middle.
What an evening actually looks like
One person opens a case. Everyone else scans a code and the case opens in their browser — nothing to install, no accounts, no passing a phone around the table. If someone shows up late you hand them the code and they are in.
Everyone gets a role only they can see. One of those roles is guilty, and — this is the part that changes the shape of the whole evening — the culprit knows from the start. They are not discovering it along with everyone else. They spend the hour explaining themselves at the same table as everyone else, in real time, with everyone watching.
After that, nobody runs anything. There is no narrator calling for night and day, no turn order, no cards to draw. The game is the conversation: what you were doing, why you were there, what you noticed about the person opposite. Your phone sits face down for most of it.
At the end, everyone accuses at once. Then you find out.
Nobody is eliminated at any point. That was not a small design decision — it is most of the reason the thing exists. An hour is a long time to sit out.
Who it is for
Four to six people. This is the size we built for, and it is the gap we kept falling into: too few for Mafia, too many for a two-player board game, and a Friday where five friends are already at the table. Hidden-role games need a crowd to give liars somewhere to hide. A detective case does not — five people and one liar is plenty of pressure.
People who like the idea of a murder mystery but not the logistics. If you have ever looked at a kit, priced it, seen “allow one week for preparation” and closed the tab — this is that evening without the week.
Groups who are done with Mafia. Not because it is bad, but because you have played it enough to know exactly how the first ten minutes go.
Board gamers between heavy games. It fills the slot where a big box is too much and a card game is too little.
The cases are written, not generated — each one is a self-contained evening with its own setting, its own table of people and its own reason someone is lying. We are deliberately not saying more than the setup here, for what should be obvious reasons.
Try it tonight
The first case is free and plays in the browser right now — no install, no account, nothing to buy to find out whether your group likes it. Grab four friends and see whether you can spot the liar at your own table.
Guilty Party — a murder mystery party game
If you already play Hidden Agenda, this is by the same studio, built for the other half of the evening: the part where everybody sits down.
Frequently asked
What is Guilty Party?
A murder mystery evening for four to six people that runs without a host. One person opens a case on their phone and everyone else joins from their own browser by scanning a code. Each player gets a private role, the culprit knows who they are from the first minute, and the group accuses once, at the end.
Do we need to install anything?
Only the person opening the case needs the app. Everyone else plays from the browser — they scan a code, the case opens, and that is the whole setup. It matters more than it sounds: getting five people to install something before a game starts is where most party evenings quietly die.
How is it different from Mafia?
Two things, and they are the two complaints people have about Mafia. Nobody moderates, so no one has to give up their evening to narrate. And nobody is eliminated — every player keeps their role and stays in the conversation until the final accusation, instead of watching from the sofa after round one.
How many players does it need?
Four to six. That is deliberate: it is the size where Mafia and Werewolf stop working because there is nowhere for a hidden player to hide, and it is also the size most evenings actually are.
How long does an evening take?
About an hour. The phone is barely involved — you open it to read your role at the start and again at the end to accuse. Everything between those two moments happens in conversation at the table.