There is a roleplaying game in each and every person who has played one.
A.D.A. is a solo roleplaying game about an Agency trying to find and detain mysterious artefacts, before they can wreak havoc on the world. The goal is to protect the public and keep the existence of these powerful artefacts hidden.
The player has to investigate strange occurences to find what the artefact is and how to detain it. Often the artefacts are used by other people or sought after by cults or shady organisations. So some force might be needed.
You can also read on some of the design process in the blogposts below.