What is Loveless?

After the death of his brother Seimei, twelve-year-old Aoyagi Ritsuka transfers to a new school to escape. On that day, he meets Soubi, who claimsto have been Seimei's friend. He soon finds out that Soubi was Seimei's "Fighter" and that his brother was killed by the "Seven Moons." Upon learning this, Ritsuka is determined to find out the truth behind his brother's death, no matter what it takes.