Every few hundred years, good and evil wage a Holy War. On one side, the Goddess Athena leads her 88 Saints in order to protect the world from destruction. On the other, Hades, God of the Underworld, commands his 108 Specters to sow chaos upon the face of the Earth. But in the 18th century, the repeating cycle of war takes a new twist, as the reincarnations of these powerful entities happen to be friends! Having growing up together in an orphanage in Italy, Tenma, Sasha, and Alone thought they would be together forever, a promise they remember by flower bracelets each of them wear. It wasn't to be, however, as Sasha turns out to be the reincarnation of Athena, Tenma the reincarnation of the Pegasus Saint, and Alone... the reincarnation of Hades! Now the battle rages, with Tenma struggling to find the strength to protect his friends. Can he keep Athena safe while fighting against his best friend? Must Alone perish so that the world can be saved? And will the three of them be able to keep the promise they made as children?