Prologue: The Verge of History
Robin (the player character) is found lying in a field with no memory. After he/she helps Chrom fend off a band of brigands, they are welcomed into the Shepherds as a tactician.
Chapter 1: Unwelcome Change
A chaotic night in the woods brings tremors and terrors, but a swordsman named Marth comes to the rescue. Back in Ylisstol, Robin meets Emmeryn, the Exalt.
Chapter 2: Shepherds
Lissa introduces the other Shepherds. They head north to Regna Ferox to seek military aid against the creatures from the woods, now named "Risen".
Chapter 3: Warrior Realm
At the Longfort dividing Ylisse and Ferox, the Shepherds are taken for brigands and attacked by the Feroxi Guard. A show of force clears the matter up.
Chapter 4: Two Falchions
To secure Ferox's aid, Chrom must defeat Marth in combat and win East-Khan Flavia the throne. Meanwhile, the kingdom of Plegia kidnaps Lissa's friend Maribelle.
Chapter 5: The Exalt and the King
Emmeryn confronts King Gangrel of Plegia, who demands the Fire Emblem, an item vital to the world's future. The parley ends with a declaration of war.
Chapter 6: Foreseer
Marth warns Chrom that Exalt Emmeryn will be assassinated. The plot is thwarted, but Marth is revealed to be a woman - and one with knowledge of the future.
Chapter 7: Incursion
While escorting the exalt to safety, the Ylisseans are ambushed. Emmeryn gives Chrom the Fire Emblem and return to Ylisstol to protect her people.
Chapter 8: The Grimleal
Chrom and Lissa learn their sister is to be put to death, and launch a rescue mission. On the way, they battle the Grimleal: the Fell Dragon's loyal followers.
Chapter 9: Emmeryn
The rescue fails, and Chrom is forced to choose between the Fire Emblem and his sister. To spare him and the world further conflict, Emmeryn ends her life.
Chapter 10: Renewal
Emmeryn's death devastates Chrom, but Robin offers words of support. They depart for Plegia to settle matters with King Gangrel once and for all.
Chapter 11: Mad King Gangrel
Gangrel is defeated. Two years later, Chrom has married and sired a daughter, Lucina. Upon learning the Valmese Empire will invade, Chrom departs for Ferox.
Chapter 12: The Seacomers
At Port Ferox, Chrom's men and the Feroxi barely repel the fierce Valmese attack. They will need ships to drive Valm off, and turn to an unlikely ally for help.
Chapter 13: Of Sacred Blood
While meeting with Validar - now king of Plegia - Robin sees a man who could be his twin. That night, he learns he is Validar's son.