Cloud9 takes place in a steampunk-esque world where most of humanity has been lost to full-scale biological warfare. The vestiges of mankind reside on a dozen Clouds - chunks of different countries suspended by a lighter-than-helium compound known as Aviosphic. Society is supported by this same compound, running all power across the Clouds like steam.

But lately, two great problems have begun to arise: firstly, Cloud 9 - Tokyo - has begun to fall back to the 'red zone' of the Vladimir Fog (Vladimir being the name of the biological weapon that killed the world). Secondly, a large number of people have been going missing from Cloud 9. It is up to the C9DA (Cloud Nine Detective Agency) to find the cause of these disappearances.

In the middle of this investigation is the newest intern from Seigami Orphanage, Kibiko Sorayama. She is joined by Shugi Tougo'oni, an anarchistic genius deeply interested in these recent disappearances, and Shizume Hikaguchi, a detective of twenty years that was caught in an in-action "unforseen circumstance". This cost him his right arm (which has now been replaced by a Aviosphic-powered mechanical arm) and has given him a rather unusual trait - he is only able to talk in quotes from Shakesperean Works.

Based on the new audio-comic series Cloud9
Written by Caleb "Catog" Robinson-Cook
Art by Alexia "alex-the-dreamer" Kalligeraki