Lost in Harmony is a musical runner game that follows two storylines. One follows a teenage couple who live together in a futuristic dystopian city, and a robot from from space who crashes to Earth while escaping his handlers.
Players follow the protagonists as they run away from the action, rather than run towards the action in a runner. Gameplay is divided up into two sections: avoiding obstacles while collecting stardust, and rhythm game sections where players press buttons in time with the background music with the aid of a chart.
The game follows two intersecting stories:
- Kaito's Adventure: a story following Kaito and Aya, two teenagers who live day to day in a futuristic dystopian city run by an authoritarian regime.
- M.I.R.A.I's Escape: a story following a robot named M.I.R.A.I who eludes his alien handlers following a daring escape and crashlanding to Earth.