Tsukihime is a doujin visual novel, released in December 2000 by TYPE-MOON. It tells the story of Tohno Shiki, who since a life-threatening accident in his youth is cursed with the ability to see "lines" on everything around him. Lines along which objects can easily be cut.
Having lived with foster parents for seven years, Shiki is recalled to the household of his family. He had lost all contact with his family over this entire period, making it difficult for him to get used to the new situation. As he gradually learns more about his past, the situation becomes more and more unfamiliar and dangerous.
Please note that this game contains some scenes of adult nature and extreme violence. Be sure to keep it away from children as they may choke on the chunky bits of dead people.