Fódlan is a land long scarred by war, but has at last achieved peace and harmony under the watchful eye of the goddess.
It is the Imperial year 1179, and Fódlan's three powers—the Adrestian Empire, the Holy Kingdom of Faerghus, and the Leicester Alliance—exist in tenuous balance.
Byleth, a wandering mercenary and the game's protagonist, chances upon three youths being pursued by bandits. As they rescue youths alongside their father, they discover that these are no ordinary teenagers, but are in fact students of the Officers Academy at Garreg Mach Monastery—and what's more, each is the heir to one of Fódlan's three great factions.
This twist of fate leads Byleth to travel to Garreg Mach, at the center of the continent, and become appointed as a professor at the academy. There they take on a colorful class of students, and find fulfilling personal growth in guiding them to success. But these peaceful days are not to last, as a dreadful plot unfolds in the shadows and draws Fódlan ever closer toward an all-consuming conflict.

This game's most distinctive feature is its branching story lines. The player's choice of faction has a massive impact on the protagonist's place in the world, and each story path features an entirely different series of events culminating in a different ending.
Whatever path they choose, players will have a home base at Garreg Mach Monastery, where they can teach their allies, sharpen their skills, and deepen their bonds with one another through extracurricular activities between battles.
In combat, players face off against brand-new gigantic enemies known as demonic beasts, and can augment the capabilities of their units with supporting battalions. Each battalion comes with a special action, called a gambit, which when used skillfully can completely turn the tide of battle.