Fate Codex

Improvisational Mysteries

by Felipe Real

One of the greatest strengths of the Fate system is its flexibility when it comes to telling different kinds of stories. Despite this, there are a number of genres that are usually considered to be difficult or even problematic to model.

Mystery is one of those.

However, both Fate Core and Accelerated are not only great when it comes to telling mystery stories, they are also some of the best RPG systems to do so. The gaming framework of Fate provides a unique experience when it comes to the genre—that of an improvisational mystery game.

What Is a Mystery?

For mystery stories in literary genres, there are usually at least three characteristics that describe what we have come to expect from this type of story.

Mysteries Are, Well, About Mysteries

From an enigmatic death to a crime that needs to be elucidated, the core of a mystery story is the act of investigating an unknown in order to reveal the “truth” behind it.

The Protagonists of a Mystery Are Investigators

Although they can be men and women of action—and they often are—the protagonists of mysteries usually have some combination of brilliant minds, powerful instincts, or even supernatural perceptions. With these abilities, they approach the unknown through careful observation and are typically more interested in unveiling the truth of the matter than other goals, such as serving justice with their bare hands.

The Antagonists of a Mystery Are Present from the Very Beginning

Since the mystery is basically a confrontation between those who want to know the truth and those who would have it remain hidden, the antagonists have to be present in the story from an early stage. In some stories they are even identified as such—the “suspects.”

The Fate Mantra and the Mystery Genre

In order to evaluate if a type of story fits the Fate system, you have only to resort to the basic “mantra” of the game, as presented on page 18 in Fate Core, where it explicitly mentions that the game “works best when you use it to tell stories about people who are proactive, competent, and dramatic.”

The mystery genre fits the bill perfectly. Investigators in all kinds of mysteries are always proactive and competent, perfectly capable of confronting both the unknown and the suspects with both expertise and skill.

Furthermore, drama is an essential part of mysteries. Even in its most “tame” form, the stakes for both investigators and suspects are always high. For the former, the stakes could be monetary compensation for proving someone’s innocence, whereas for the latter the result of the investigation could bring catastrophic consequences, including huge losses or even jail time.

As such, mysteries can be run as comfortably with Fate as action, pulp, or any other kind of “heroic” fiction. The real question, then, is how to make the best out of the Fate system for this genre.

The Classic Mystery

One possibility is to present a mystery as any other type of story. The players create the setting and their characters, the GM presents the inciting incident, and the game progresses as usual, one scene after the other, until the PCs discover the culprit the GM has determined beforehand.

This isn’t the optimal way of employing the Fate system when it comes to running mysteries, however. It kills the drama for at least one of the players: the GM. If the GM already knows who committed the crime and how, what surprise is there in the game for them? One of the most fundamental joys of playing a mystery is to be, as an audience, a kind of investigator, and if the GM knows the answers then they are deprived of that joy.

This has been a common manner of running mysteries in RPGs since at least Call of Cthulhu (CoC). Nevertheless, Fate is different enough from CoC to deserve its own way of approaching mysteries—one that relies on the robust narrative framework of the game to explore the genre from a somewhat different angle.

The Improvisational Mystery

What would happen if instead of deciding before sitting down to play who the culprit is and why, you only presented the PCs with a number of possible suspects and had no definite answer to the mystery? First, you would be following the genre’s main tenet: finding the truth about a mystery through careful investigation. Second—and more importantly—you’d be enjoying the experience of investigating as much as the other players at the table.

The improvisational mystery is, then, a way of running a mystery in Fate by playing on the strengths of the system, as well as adhering to the traditionally fundamental characteristics of the fiction it’s trying to model. The main precept is that, as long as you present all the necessary information to the players and develop well-rounded suspects, you don’t need to know the solution of the mystery in advance.

Present All the Necessary Information

The first and perhaps most important principle is simple: you must provide the PCs with all the relevant information—aka “clues”—needed to solve the mystery.

One of the carryovers from D&D that made its way into a radically different game as CoC was the adversarial position of the GM. This, in the case of an investigative RPG, got reflected in the misled notion that PCs have to succeed to obtain the necessary information to reveal the truth of the mystery. This has led, in the best of cases, to an overreliance on lucky rolls and high skills and, in the worst, on games that got stuck because nobody had any idea where to go to next because of insufficient information.

Visualize mysteries as puzzles. The exercise and ability required to solve both is the same: you have to put the pieces together in order to see the full picture. However, who could do that if there were missing pieces? Maybe a couple missing pieces wouldn’t derail the endeavor at large, but what about those that connect and give meaning to the whole? Those that really help you reveal the big picture?

In the case of improvisational mysteries, then, the solution is simple: you give all the relevant information to the PCs at all times, no matter the result of the dice. You don’t withhold information from them because, in fact, you don’t have any extra information; you’re discovering the truth about the mystery along with them.

The only caveat is that the PCs have to ask for the information.

The PCs Are Investigators—and They Should Act Accordingly

“Investigators” is not a cute way of referring to the PCs: it’s a fundamentally different way of approaching the game. Yes, the PCs are still as proactive, competent, and dramatic as in any other great Fate game, but their most important skill and/or approach is not written on their character sheets. What makes a PC an investigator is an inquisitive mind.

Or, in other words, asking questions.

Encourage your players to ask questions at all times. When they enter a zone in a given scene, provide the simplest description and let them explore it with their actions. When they answer your familiar “What do you do?” with prepackaged answers such as, “I search the room,” pressure them. “What are you looking for?” and “How are you searching?” are great starting points, but you have to go even further. Remember that these questions are the way in which you are discovering the clues that will lead the investigators—and yourself—to discover the truth behind this mystery. The PCs as investigators will provide you with the clues—your role isn’t to create the clues but to join them together in one logical and coherent story.

When to Roll—and What the Results Mean

The correct place of rolls—and their interpretation—in an improvisational mystery isn’t whether or not the clues can be uncovered, but in how they are uncovered.

Or, in other words, at what cost they’re obtained.

Imagine that the investigators are working on an unsolved murder and you, running an improvisational mystery, are willing to provide them with all the relevant information necessary to solve it. The question is, how do you provide that information while still integrating skill rolls?

The answer: you have them suffer the consequences of their acts.

To follow with the unsolved murder, the PCs ask questions and act on the crime scene where the victim’s body was found. An investigator says, “I look around the room in case something catches my attention.” In that case, if you’re playing in Fate Core, you could have them roll Notice to create an advantage; if you’re playing in Fate Accelerated, you could have them roll the corresponding approach, probably Careful.

No matter what happens, the PC will get at least the necessary information to keep the investigation going. In this case, they’ll find out at least a clue that points to one or more suspects as the culprit. Remember: they’re the ones creating the clues, saying what they find, while you interpret the results of rolling, saying what consequences they suffer.

If they succeed in a roll, you should ask them, “What did you find?” They in turn might answer something like “A fingerprint.” Since they succeeded, they suffer no consequences. So, they receive the Complete Fingerprint aspect with one free invoke. The fingerprint is useful, clean, it can be used in court, and it’s properly stored, for example.

If they tie, you still ask “What did you find?” When they mention the fingerprint, you should probably modify the result to A Partial Fingerprint and, as per the usual rules, it’s only a boost now. This will, in turn, create tension for the investigators, as they have to decide when to use that boost to their maximum advantage. They have a key piece of the puzzle, yes, but they aren’t free to use it as they please. In this case, the fingerprint may decay over time, be extremely difficult to process, or otherwise last for a very short time; the PCs have to find the best way to use it—and they have to find it now.

If they fail—following the rules as presented in Fate Core—again you would ask, “What do you find?” But in this case, with the same answer (a fingerprint), the investigators would still get the aspect Complete Fingerprint...but the free invoke goes to their opponent: in this case, one or more of the suspects. Maybe the investigators found a complete fingerprint, yes, but one that incriminates someone innocent instead of the “real” culprit. Or perhaps the investigators lied about their identities or entered private property without the necessary permissions, both situations earning them the mistrust of government authorities and even some legal problems of their own. Go with whatever fits the fiction—and the suspect’s modus operandi—better.

In all cases, the investigators obtained the clue necessary to continue their investigation, no matter the result of the dice. A clue that, in fact, you never even knew about! The important thing is, once again, not to decide in advance what the clues are going to be and, instead, leave the PCs to invent them.

What you should not do here is intervene and say what they find; instead, let the investigators decide. They’re leading the investigation and you’re just making the necessary connections in order to give shape to the overall story. In an improvisational mystery game, your role is not to hide the necessary information behind the rolls, but to string together the results in such a manner that moves the story forward.

It Starts with the Victim

The best way to run a successful improvisational mystery is to develop robust suspects. This is the only part that’s truly yours as a GM, and it should be the focus of your pre-game preparation. In order to do this, you need to start with the center of the mystery: the victim.

Depending on which type of mystery you’re running, your victim can be dead or alive—or even both. In any case, you need to develop this character in as much detail as possible. In Fate terms, write a character sheet as complete as that of the investigators, and pay special attention to the relations of the victim.

You started out by deciding on a classic victim: an old millionaire who has been found dead. The victim, in this case, has a number of relations that, in turn, will form the base of your suspects. You have the young spouse who got married only because of the money; the children that could benefit from the inheritance; the ex-spouse that is still heartbroken after their separation; etc. All of these relations have the potential to be suspects and, in turn, to become the culprit behind the murder.

Know Your Suspects

Now you develop the suspects in a robust and simple way by following these three simple steps:

Give every suspect a good motivation to be the culprit.

If you give every suspect a reason to have committed the crime in question, you will have all the necessary tools to improvise their behavior no matter what the investigators do.

This motivation emerges from the relationship they have or had with the victim. The motivation can be as simple as a desire for revenge or a monetary benefit, or as twisted as a misguided sense of duty or a perverted notion of love.

This is the one thing you absolutely must know in advance in order to run the suspect properly.

You are running a 1920s cosmic horror mystery. A professor died under mysterious circumstances and one suspect immediately comes to mind: a former student. What motivation could she have to kill her mentor? He refused to provide her with the material necessary in order to continue her enquiries into forbidden knowledge, afraid of the consequences. She, however, seems obsessed and would probably stop at nothing to learn more about the topic.

Give every suspect an alibi.

This is what allows you to run a truly improvisational mystery. If everybody has a reason to be the culprit and a good explanation for it not being them, everything is up in the air. The result of this combination is that, even though you can have some idea of who could have committed the crime, every suspect can turn out to be culprit without hurting the sense of logic or the suspension of disbelief necessary to make your game a satisfying experience for everyone at the table.

The student of the occult is obsessed and on the brink of madness, it’s true, but it’s because she was secretly in love with her teacher, and not because of his access to the restricted section of the library. This facet of her character, however, will only come to light if the characters lead the investigation to the conclusion that she’s not the culprit. If they decide that she’s the culprit, this alibi can be twisted to become part of the suspect’s motivation to have committed the crime.

Develop the suspects as much as you need to—and nothing more.

Apart from the motivation and alibi, you don’t need to develop much more of the suspects in order to run them properly. It’s a bonus if you can give them a good—i.e., easy-to-remember—name, a couple of personality traits, and maybe a distinct voice, but only the motivation and alibi are absolute musts when it comes to improvising their behavior. Everything else should and will evolve as a natural result of the understanding that both the motivation and alibi provide of the suspects’ inner workings.

The danger, instead, is in developing too much of the suspects’ inner workings. The more you develop a suspect, the less flexible you’ll be at the table to accommodate the investigators’ findings. Even worse, too much development—especially the kind that’s inclined toward specific descriptions and convoluted motivations—creates suspects that end up being neither useful nor easy to run on an improvisational mystery, defeating their purpose.

At the Table

Here are some techniques, tips, and advice that may help you to run an improvisational mystery at the table.

The More You Improvise, the More Structure You Need

Sounds like an oxymoron, but the truth is that improvisational mysteries require quite structured game play. Even more so than in other Fate games, you must be aware of beginning—and, more importantly, ending—scenes when necessary. Don’t tarry or delay on irrelevant details. If the PCs are figuring out the puzzle on the run, battling against time and/or their enemies—as they should—do not stop the action to describe the minutiae of three long hours of reading at the library; just note the passage of time, if necessary, and ask the players, “What did you find?”

Run the Suspects with Gusto

Don’t fall into the clichés. Go for the twist, the surprise, and the unexpected; make your suspects memorable and play them with as much love as your players put into their PCs. Feel free to actively work against the PCs, but do so in such a way that makes the investigation more exciting, not more oppressive. Also, consider logic and plausibility: geniuses like Moriarty should be the exception, not the rule, and the conflict should be unfair only if that creates a high stakes situation that can later be confronted by the PCs in a more or less advantageous manner. As always, do whatever fits the story, the PCs, and the suspects’ motivations better.


Make the investigation something exciting in and of itself. In this case, use the PCs’ answers as a jumping point to describe the clues and situations in as much as detail as the story demands. Make your descriptions as grounded or fantastic as you want, but, above all, make them memorable. Follow the tropes corresponding to the subgenre of mystery you’re using as framework and, if necessary, subvert or even throw them out the window. However, never sacrifice the delivery of clear and useful information for flavor and flourish.

Pressure the Investigators

Don’t let the investigators go about their businesses without opposition. Use your suspects cunningly, and make the investigation as painful and grinding while still entertaining—without denying the investigators the essential information to solve the mystery. Extend the web of relations beyond the suspects and explore their other relations: the current partner of the vengeful ex-husband, jealous of the—apparently murderous—intention the ex received; the lawyer of the only heir that could benefit greatly from an unfortunate accident to her client; etc. All of these help to make the world of the investigation come alive, deepening your players’ immersion while developing a rich setting you can keep coming back to whenever you want.

Make the Mystery Important and Dramatic

Try to make the results of the mystery something relevant to all the investigators. Make them have personal stakes involved and don’t encourage an emotionally detached attitude to the game. If anything, inspire yourself in the classics of noir or hardboiled stories and encourage your players to create overly dramatic, overblown characters. Aim for the larger-than-life personas, the all-or-nothing characters that live and breathe to uncover to truth no matter the costs. This is a crucial part of your role during character creation, but even after that you should try to tailor the story—and especially the suspects—to the specific investigators trying to solve the mystery.

Listen to Your Players

Let them create the clues and listen to their speculations. Allow them to discuss and theorize at large; if they’re entertained, leave them be. If not, throw some opposition their way and provide them with more information. Don’t play the game of red herrings; if they agree on a theory, let them get to the bottom of it and discover it to be the truth. Your role isn’t to withhold information; it’s to provide a satisfying investigative experience for everyone at the table, including yourself.

Give Them More Information than What They Need

Don’t be afraid to provide the players with more information than they can possibly need to resolve the mystery. Remember: the game is not about denying them clues, but about making the investigators pay for them in sweat, blood, and tears. Use every roll of the dice to provide them with more information and, at the same time, gather as many “resources” as possible—aspects, invokes, compels, etc.—for the suspects to escalate the stakes of the investigation.

In Conclusion

Running an improvisational mystery may seem like a daunting task at first, but with the right mindset can be one of the most satisfying experiences. The excitement of discovering the truth along with the players—instead of frustratingly waiting for them to figure out your truth—is something that few RPG systems can offer. And if there ever was one up to the task, that has to be Fate.