The Year is 2422, 100 Years after the Great Invasion. Although Humans have managed to fend off the invader the damage that has been done is too great, making the entire earth a wasteland. Fresh food and water became scarce. 50 years ago with the technology they stole from the Invader they managed...

William signed a pact with Akane and Aoi. What’s the cost? Well, it’s definitely not a normal adventure. Who and what they will meet in theirs adventure?