C³ or the full name is Cube x Cursed x Curious (C3 -シーキューブ-) is the story of young boy named Haruaki Yachi (夜知 春亮), ordinary boy who has a special power that can defeat all of curses. It makes him must serve to withdraw curses of various items that his father usually sends to him regularly. One day he received the very heavy black cube from father in a foreign country, when he tried to open then he was the cube hit head, he knew that this is the new curse item that his father sends it for him to solve the curse like always. When he was still unable to open it, then take a nap to find a way to solve the curse in the next day, and on that night, Haruaki needs to wake up because heard strange sounds in the kitchen.
When look in the kitchen he met with the bare cracker thief girl, which she said that itself was the curse cube that he tried to open earlier. She has suggested that her name is Fear, the curse cube that will be cursed to those who try to open must die but except Haruaki Yachi also the curse will not affect anything to him. He also makes Fear turned into the little girl as well. Fear knew that Haruaki Yachi has the power to resist the curse in which she asked him to help solve the curse that attached to Fear. The chaos story has already occurred!