A world with two kingdoms: the Emblian Empire, which wishes to rule all worlds, and the Askran Kingdom, which stands in its way. Players take on the role of summoners with the special ability to call upon legendary Heroes from different Fire Emblem worlds. In order to save the Kingdom of Askr from destruction, they join Prince Alfonse, Princess Sharena, and the Order of Heroes in fighting to stave off Embla's advance. As they struggle to thwart Embla's ambitions, they will find the mysteries of this world unraveled before them piece by piece.

This is the first Fire Emblem game to appear on mobile devices. To support the original cast of characters from the Askran Kingdom, players call upon popular personalities from other entries in the series as Heroes and mold them into an effective fighting force. Though the overall map size has been reduced to accommodate smaller screens, battles are chock-full of familiar Fire Emblem mechanics like terrain restrictions, movement types, and support bonuses that encourage players to experiment and strategize. Additionally, players can also square off against one another's teams in competitive modes such as the Arena and Aether Raids.