JO.

Product designer

Case 04 / Concept, social game and AI

Plotline

An AI game master that turns a group chat into a multi-day mystery, so nobody has to host and everyone gets to play.

Year
2026
Timeframe
1 month
Role
Product designer: research, brand and UI
Tools
Figma, Illustrator, Claude, After Effects
Plotline cover: the line Someone in this chat is lying above three phone screens of a murder mystery game

The 30-second version

01 Problem

Every group game needs a host, and the host never gets to play. Someone has to keep the secrets and know the twist, party kits need everyone in one room on one night, and quick social games never build into a story.

02 What I did

I designed the brand and design system, 30 screens for iOS and Android, a creator studio on the web and a website. The AI is the narrator and referee, never a player. It improvises only inside beats a human wrote, and it shows its work at the end.

03 Outcome

Plotline is a concept, so nothing here is a measured result. I set targets for a pilot with 50 crews: 70% of campaigns finished, 75% of players playing daily, 30% of crews starting a new game, and fewer than one report per 1,000 turns.

Friends don't need more games. They need someone else to run them.

01Four rules

Calm by default: one clear action per screen. Every screen is a moment, built to be screenshotted. Secrets feel secret: private screens go indigo. Play first: the rules are one tap away.

02A host that never sleeps

The game master writes a chapter every morning from what the crew did the day before, so every move changes something visible in the story. The tone follows the genre and the crew's spice level, and a twist arrives when the chat goes quiet.

03Secret mode

Each player holds a secret role, so private screens had to feel private at a glance. The best tool for secrecy turned out to be a mode switch, not a new design: the same components, gone indigo.

04What I learned

Pastel accents work best one at a time. A single soft colour per screen kept 30 screens calm and readable. And an AI game master earns trust by showing its work at the end.

Next I would test whether crews finish 5-day games or need a 3-day default, how players feel when the AI plays a missing friend's minimum moves, and whether creators want revenue share or just an audience.

Case study boards (15)

Plotline case study board: Overview
01 Overview
Plotline case study board: Problem
02 Problem
Plotline case study board: People
03 People
Plotline case study board: Insight
04 Insight
Plotline case study board: Designing an AI game master
05 Designing an AI game master
Plotline case study board: App structure
06 App structure
Plotline case study board: Brand and system
07 Brand and system
Plotline case study board: Secret mode
08 Secret mode
Plotline case study board: Getting started
09 Getting started
Plotline case study board: Role reveal
10 Role reveal
Plotline case study board: Story and quests
11 Story and quests
Plotline case study board: The finale
12 The finale
Plotline case study board: Creator studio and marketplace on the web
13 Creator studio and marketplace on the web
Plotline case study board: Website
14 Website
Plotline case study board: Outcomes and reflection
15 Outcomes and reflection
Josh Opaleke, portfolioWaking up 000