Nobuo Koyama, a manga artist and father of Kadode Koyama, wakes from an eight-year coma inside a crowded shelter camp built after the alien mothership's fall over Tokyo. Two young women there tell him he wasn't simply asleep: something happened to him during those missing years that he can't remember and they won't fully explain. While the noxious fog from the mothership's wreckage keeps most survivors underground, Nobuo has one goal: find his daughter Kadode in a city that has changed more than he can process. Numbered Episode 0 but set partway through the story, this standalone entry serves as a prologue for the ONA series.