Following Keita's sudden death, Hibiki remains visibly shaken due to the fact that they couldn't prevent it. As Merak arrives in the city, Yamato has JP's members move Hibiki into position to intercept it. At the Osaka Juso Ohashi Bridge, the Japanese military tries and fails in their attack against Merak while Botis and "The Anguished One" discuss the state of affairs. With of the loss of most Osaka's spiritual barriers, Merak fully manifests itself and makes its way to the final barrier - "Tsutenkaku". Meanwhile, as Hibiki is deployed into the field, Hinako and Io discuss his mental state due to Keita's death. Meanwhile at the Umeda Sky Building, JP's summoners try to stop Merak with a swarm of Itsumade but it kills them all in an instant. As Io heads to Hibiki's location, Merak then launches a devastating ice attack, at the "Tsutenkaku" barrier, which survives, but the attack leaves a path of destruction and kills many more people, upsetting Hibiki.
The countdown to extinction begins on Sunday with the arrival of the Septentriones, otherworldly invaders set on the eradication of mankind. Caught in the crossfire, Hibiki Kuze and his friends join in the war for humanity's survival by signing contracts with demons to become "Devil Summoners." Soon, their abilities attract the attention of JP's, an underground agency led by Yamato Houtsuin. Once recruited into JP's, Hibiki and his friends fight and bond alongside other ordinary citizens who are Devil Summoners.
However, with each new day, another Septentrione appears to wreak havoc upon Japan. Even if many lives are lost in the process, before that night ends, the young summoners must defeat the invaders at all costs.
