C³ summary: One day the high-school student Yachi Haruaki received a mysterious black box sent by his father from abroad. It was a “Cursed” object which could a.s.sume human form. The black box whose name was Fear came to Haruaki wanting to rid herself of the curse. Together with Haruaki and his boarder Konoha, Fear decides to do helpful things in order to neutralize the negative energy that was built within her, to be free from the curse that bound her.