In a country where companies are categorized into many subdivisions and corporations, only one of them is a ghost corp—the Phantom quest corp. When otherworldly supernatural phenomenon threatens the city and its populace, Ayaka Kisaragi and her employees are on the job to fight any and all supernatural menace.

Ifrit, who has been trapped in Rimuru due to the latter's Predator skill, recaps events of the season while in a discussion with Veldora as they play Shogi.

A great evil is sweeping over the realm; an evil that the young swordsman Roan and his life-long companion, the acolyte Yufa, must face head on! For these two travel toward their destiny, from the highest towers to the depths of the underworld, through forest and desert alike. With an ever-growing cast of fellow heroes, fate will grasp these travelers by their very souls and propel the band of skilled adventurers towards a noble end. Or ignoble, if they don't watch their step! Monsters are afoot and the way rife with danger and magic, the path forward may be unclear... But where will is strong, there is a way! Lessons wait in the depths of darkness, and good must prevail. The journey starts now!

In Iraq, a group of archaeologists discover ancient relics that prophecize the coming of a superior race and the end of all civilization. Meanwhile, back in Graviton City, as A-Ko and B-Ko's rivalry over Kei intensifies, Mr. Daitokuji sets up an arranged marriage between Miss Ayumi and Kei. Furious over the engagement, both A-Ko and B-Ko do whatever it takes to prevent the wedding from going through. Little do they know that another alien fleet is on its way towards Earth.