They are neither plants nor animals. They differ from other forms of life such as the micro-organisms and the fungi. Instead they resemble the primeval body of life and are generally known as 'Mushi'. Their existence and appearance are unknown to many and only a limited number of humans are aware of them. Ginko is a 'Mushi-shi' who travels around to investigate and find out more about the 'Mushi'. In the process, he also lends a helping hand to people who face problems with supernatural occurrences which may be related to the 'Mushi'.