Hibiki awakens on Thursday and to his surprise, finds Alcor waiting in his quarters. Over coffee they casually discuss the state of affairs. Hibiki, now believing that Alcor isn't a threat, gives him sanctuary in his JP's quarters, with a promise that he not reveal himself and what he actually is to anyone, for fear of creating a panic within JP's. Just then, Daichi and Io enter Hibiki's quarters and find Alcor, much to their shock. Although, Hibiki is forced to confide in them about Alcor's nature. Later that day, Airi and Hinako are selected by Makoto and Fumi to challenge the next Septentrione. Much to Hibiki's reluctance to let them fight, Makoto explains that the Septentrione: Alioth is scheduled to manifest in the Earth's Ionosphere, and hence, specialized long ranged demons that only Hinako and Airi can summon, stand any chance of attacking it.
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.
