In a land where fallen angels descend on Sunday mornings, a young boy named Michel lives alone after losing both his parents to illness. To survive, he sometimes resorts to theft, and he spends his days scavenging among the corpses of fallen angels. One day, he finds an egg inside the body of a dead fallen angel and brings it home. From that egg, a fallen angel is born, and Michel names her Bubu. Bubu is innocent and carefree, a stark contrast to Michel’s lonely and hard life. Despite the joy Bubu brings, a dark omen hangs over them: it is said that fallen angels eventually become demons and will take the life of the person they are bound to. As Michel and Bubu travel together, they encounter various people and experiences that deepen their trust in each other. The story follows their journey of love and bonding, exploring whether the bond between a deeply wounded boy and an innocent fallen angel can overcome the fate that threatens to tear them apart. Their future remains uncertain, and the choices they make will determine whether they find happiness or tragedy.