As the clock ticks towards doomsday, the Seven Heavenly Virtues descend on Sunday, heralding the impending extinction of humanity. Hibiki Kuze and his comrades find themselves thrust into the battle for mankind's survival as they forge pacts with demons to become 'Devil Summoners.' Their unique skills catch the eye of JP's, a clandestine organization led by Yamato Houtsuin. Enlisted into JP's ranks, Hibiki and his friends unite with fellow ordinary individuals turned Devil Summoners, facing the relentless onslaught of the Septentriones ravaging Japan day by day. Sacrifices mount as they strive to vanquish these cosmic intruders before the sun sets, determined to safeguard their world at any cost.