In the world of Nion, people everywhere are accompanied by beings know as Spirits which are referred to as Spirit Partners, these Spirit Partners come in man shapes and sizes, and are typically resemble small animals. Minato Yukaze a 16 year old boy who lives on Nion, is moving to the port town of Shel, with him he brings Lunellea, his Spirit Partner, who unlike most Spirit Partners resembles a human girl, but there another thing that makes her vastly different from others, Free Will, and somehow that is related to why he's moving to Shel, what happened back home that is making Minato move away from his home?, and will he be able to keep Lunellea's Free Will a secret?