“You’re basically the DM”: Siobhan Thompson on bringing improvised murder mystery Denouement to the UK

British comedian, writer, and core Dimension 20 cast member Siobhan Thompson is bringing her live improvised murder mystery show, Denouement, to the United Kingdom for a six-city theatre tour from 29 May to 5 June 2027. Following a sold-out run in Los Angeles, the production visits Glasgow, Newcastle, Bristol, Birmingham, Brighton, and London, tasking an eleven-person US comedy ensemble with constructing and solving a brand-new whodunit on stage each night without a script.

Developed by Thompson and director Alex Fernie (Last Week Tonight, Reno 911!, Key & Peele), Denouement bridges structured long-form improvisation and the tabletop roleplaying games that helped make Dropout a streaming powerhouse. Alongside writing for Rick and Morty, Krapopolis, and Grimsburg, Thompson spent years at the Dimension 20 table, a live actual-play phenomenon that previously sold out Madison Square Garden. Moving from dice-driven character sheets to theatrical whodunits requires a different set of operational stage rules, especially when scaling a show built in intimate Los Angeles comedy clubs up to multi-thousand-seat British halls.

Cast and Creatives for the Denouement 2027 UK Tour

• Siobhan Thompson: Co-creator and performer (Dimension 20, Game Changer, Rick and Morty).
• Alex Fernie: Co-creator, director, and performer (Childrens Hospital, Bajillion Dollar Propertie$, Key & Peele).
• Vic Michaelis: Performer (Very Important People host, Dimension 20).
• Grant O’Brien: Performer (Dirty Laundry, Breaking News, CollegeHumor).
• Kimia Behpoornia: Performer (Abbott Elementary, Atypical, Dimension 20).
• Jacquis Neal: Performer (Crowd Control host, Comedian Clash).
• Angela Giarratana: Performer (Smosh, Team StarKid, Very Important People).
• John Milhiser: Performer (Saturday Night Live).
• Dhruv Uday Singh: Performer (Good Trouble, On the Verge, UCB).
• Cathryn Mudon: Performer (Broad City, Dollface, Tales of the City).
• Ele Woods: Performer (Game Changer, Dirty Laundry, Nobody Asked).

Interview: Siobhan Thompson on the Mechanics of Denouement

Whodunits traditionally demand meticulous reverse-engineering from the solution backwards, yet Denouement runs entirely without a script. How do you and Alex Fernie maintain plot coherence across clues and red herrings in real time so the finale feels earned rather than accidental?

This comes from many hours of rehearsal, twinned with decades of experience from everyone on the cast. It’s based on a form called the pretty flower which we’ve heavily modified to fit the genre. We’ve spent a year honing how to make this show feel both spontaneous and surprising whilst also having satisfying reveals. We get as many gasps as we do laughs which feels great. We’re all being so stupid at the very top of our intelligence.

Denouement cut its teeth in intimate Los Angeles rooms before scaling to large venues like the SEC Armadillo and Eventim Apollo. In what way does stepping onto multi-thousand-seat stages alter the pacing, physical comedy, and acoustic timing of a fast-moving mystery?

The whole cast is very experienced at playing to a live audience. For the larger venues we are very aware of having to play bigger. One of the most fun things in this show is all the farcical entrances and exits, and we’re looking forward to playing with those on even bigger stages.

In roleplaying games, dice resolve uncertainty, whereas long-form improv relies on trust, offers, and callbacks. Without mechanical prompts or character sheets on stage, what internal rules or pacing checks does the cast use to decide when a clue is definitive truth versus a suspect’s outright lie?

It just comes down to practice. We practice a LOT. And the person playing the detective (mostly me) acts as a sort of conductor, throwing to new scenes if the pacing feels like it needs it.

With an eleven-person powerhouse cast spanning varied performance backgrounds from UCB to Saturday Night Live and Smos, how do you manage spotlight distribution on stage so the investigative plot doesn’t collapse under comedic side quests?

Oh but sometimes the sidequests are what makes the show! I love a sidequest. But also, again, we’ve all known each other for so long, and everyone is very good at “this person hasn’t had a moment yet, let me spotlight them”. And hey, sometimes you’re the killer and sometimes you’re the maiden aunt who forgot how to speak because she got attacked by an Ostrich in Kenya, and both of those are fun in different ways.

Playing the central detective requires simultaneously anchoring the scene, cross-examining suspects, and acting as the audience’s surrogate. How do you rotate or approach that central role to avoid burning out the detective while keeping the suspects unpredictable?

It’s challenging because you’re kind of in a completely different show than the rest of the cast. You’re basically the DM. We’ve been rehearsing it a lot and it’s so fun, because everyone’s approach to being a detective is so different. There’s a thing in improv we call pimping, where you make your scene partner do something that they are almost certainly bad at – “he used to write poetry in French when he was in school and then recite it while doing cartwheels!” – and then you get to watch that play out. Being the detective, you’re doing a lot of that, on top of drawing everything in at the end and creating a cohesive conclusion. It’s fun!

In your previous conversations around character design for Dimension 20, you noted how crucial it is for characters to possess sharp personal blind spots. In a completely unscripted 90-minute show where suspects are invented on the spot, how do you quickly signal deep flaws and hidden motives to your scene partners within their opening lines?

The great thing about playing within a genre is that Agatha Christie et al have done a lot of that work for us. This genre plays in archetypes, and even though we’re subverting those a lot, those are our starting off points. Then we find the rest along the way.

In roleplaying games, players frequently miss vital clues or fixate entirely on decorative props. What is your mechanical recovery strategy on stage when an improviser establishes an accidental plot contradiction that threatens the logic of the case?

I actually love it when they do that, because that’s a clue. The detective is figuring out who did it at the same time as everyone else, and I know the audience is clocking those contradictions too.

The explosion of actual-play roleplaying games has conditioned audiences to appreciate multi-hour, unscripted character drama alongside comedy. How much has the mainstream success of shows like Dimension 20 paved the way for audiences to pack theatre venues for complex, non-televised long-form improv?

I think we proved that improv is more than sweaty nerds in a basement playing zip zap zop. Sometimes they let those sweaty nerds go upstairs, and that’s great.

As a British performer who established a major footprint in the US improv and streaming ecosystem, what distinct comedic sensibilities do you notice when bringing an American-styled long-form plot format back to British audiences?

It’s so funny because there is a British tradition of longform improv that has kind of gotten lost – everyone go listen to The Masterton Inheritance from the 90s, it’s fantastic. I love British comedy audiences because I really think comedy is such a huge part of British culture. The standards are so high, because great comedy abounds. It’s made my standards very high, and I’m always trying to push us forward.

When you step away from intense production schedules and high-wire stage shows, what independent roleplaying games or live creators are currently inspiring you that UK audiences ought to check out?

My favorite performer at the moment is Natalie Palamides. She’s such a fearless actor and a brilliant writer and she’s making shows that look like nothing else I’ve ever seen. Go see her live if you can.

Denouement 2027 UK Tour Dates and Venues

Quick Links

• Tickets for Siobhan Thompson Presents Denouement: An Improvised Murder Mystery went on general sale on Friday 4 September 2026 and are available via Live Nation UK.