The ones that predicted this death sentence are part of a decades-old organization going by the name of Chaldea. The gathered intellect of the world's brightest scientists and magi, a forbidden combination of talents with the intent of prolonging humanities continued existence for as long as possible. Through the advanced "projects" it had developed, Chaldea pinpointed and dealt with multiple obstacles that have threatened the world, but this one might be the toughest yet.
Legendary heroes from ages passed have been summoned and along with many mages from the present world, quest to fix the events that will cause this mass extinction. These Agents of Chaldea ignore a forbidden taboo of magecraft using the untested sixth project of the organization; Time travel. They are the ones who would rise up against human history for the sake of humans, and fight fate itself.