Fairy Gone is set in a world recovering from a war where fairies were weaponized.
Humans could become "Fairy Soldiers" by surgically integrating fairy-possessed animal organs, allowing them to summon and control powerful fairy avatars.
The story follows Mariya, a rookie member of Dorothea, an organization tasked with handling fairy-related crimes in the postwar era.
As she investigates these crimes, Mariya encounters former Fairy Soldiers struggling to find their place, some of whom turn to terrorism seeking justice or revenge for the past.
The anime explores the complex lives of these individuals and the challenges they face navigating a politically unstable world grappling with the consequences of using fairies as tools of war.