In Fire Emblem Gaiden, the story takes place on the continent of Valentia, which is divided into two different kingdoms: the Kingdom of Rigel, ruled by the Emperor of Light, and the Kingdom of Zofia, ruled by the Emperor of Darkness. Both kingdoms are facing a growing threat from a dark power that is spreading across the continent. The story follows two main characters, Alm and Celica, who come from different backgrounds but share the same goal: to stop the dark force that threatens to destroy their world. During their journey, both Alm and Celica will face difficult decisions, take different paths, and clash with powerful enemies. They will have to learn the true meaning of battle and sacrifice, while uncovering the hidden truths of Valentia's past.