What is a promise? A promise is something that's supposed to be kept. Something that should never be broken. But what happens if you can't keep that promise? Do bridges burn? Are walls built? You've both made a promise. Can you keep it?

Maple and her best friends are all in a guild called Galaxia. All of them are juniors that are still training to be a real hero one day. Once their enemy guild, Shadow Claws, finds out Maple would be a threat in the future, all hell goes loose. Maple is now the hunted. Their number one priority.... kill her.