The story of Track Zero focuses on the afterlife before the events in the anime series, before the founding of the Afterlife War Front and before Otonashi's arrival in the afterlife.
A boy named Hideki Hinata finds himself in the afterlife, which comes in the form of a vast school complex, and he meets a girl named Yuri Nakamura, who takes him into her personal mission: to provoke God and take him on personally. During their march to this mission, the two meet new allies and foes alike, and they discover the stories behind each and every one of them. This is the story of the beginnings of the Shinda Sekai Sensen.
In the epic conclusion to the Devil's Deal series, Freya has one final chance to discover the full potential of her own power, and to use it to restore balance in the universe - once and for all. After the destruction caused by Roisin, Ferya and Torix come to terms with their losses and mistakes... And prepare for a final battle that will change everything.