Just as Iska and Unit 907 finally rescue Princess Sisbell, the Lord Yunmelngen abducts Rin and orders them back to the Imperial capital. Despite the obvious danger, Iska and company hurry to the heart of the Empire to both free their comrade and discover what transpired there a century ago during the creation of witches. But neither of these tasks will be easy, for the Eight Great Apostles are determined to end Iska's pursuit of the truth. Meanwhile, disaster brews in the Nebulis Sovereignty!