The main character Lloyd Irving and his friends, Genis Sage and Colette Brunel, are sent away from the town where Lloyd lived. Genis' sister Raine and the mercenary Kratos join them. While traveling, Colette begins to change into an angel. Lloyd learns that she is in charge of saving the world. Two groups of people want her to stop. They are the Desians, bad guys that enslave humans, and Sheena, a woman that wants to kill Colette. Sheena and Colette save each other from the Desians and become friends. Eventually, they get ready to save the world. Kratos betrays Colette and the others to Cruxis, the angels who control the Desians. Lloyd and the others manage to escape. They go to a different world called Tethe'alla. There, they make three new friends called Zelos, Presea, and Regal. Kratos still wants to find them and the Cruxis leader, Mithos, is very angry. Lloyd's group learns that if they want to save the world, they need to have Sheena gain the power of the eight "Summon Spirits". The spirits are magical creatures. After using the power of the summon spirits, the problem gets worse. Lloyd and Kratos need to work together to save the world from being destroyed by the Giant Kharlan Tree. Yuan uses a drug where it puts people to sleep on everyone. After this, Lloyd wakes up in the middle of the night. Kratos is with Yuan and two of Yuan's henchman. Lloyd learns that Kratos is his father. Kratos dives in front of Lloyd to stop him from being hurt. Kratos then tells Lloyd that there is a ninth Summon Spirit by the name of Origin. Lloyd has to fight Kratos to get its help because Origin was sealed by Kratos himself. The Summon Spirit helps Lloyd use the eternal sword. After this, they go to Derris Kharlan and there is one last battle with Mithos.