The Book of Law is an encrypted grimoire that only one nun has the skills to decipher—and it’s gone missing! If its magic is ever used, it will bring about all sorts of ruin. Now, the church just has to keep the gifted nun safe. How hard can that be?

The battle over Orsola, the only nun who can read the Book of Law, continues as Toma is forced to act as an unwitting decoy. The Amakusa clash with church representatives, but the real culprit behind the plot might not be who Toma expected.

With Orsola taken hostage, Toma and his gang take the battle to the church. There, Index unleashes a mighty spell. Things look bleak for the Roman Orthodox, but their willingness to sacrifice themselves might just give them the upper hand.

The Roman Orthodox nuns continue their attack as Orsola risks everything to have Index decipher the Book of Law. The infamous grimoire could help them finally defeat their enemies—but that’s only if it works like it's supposed to.

Agnese makes a deal with Toma and Orsola that guarantees their safe escape from the Roman Orthodox ship—so long as they take Sisters Angelene and Lucia with them. As they search for the nuns, they uncover more about the ship’s terrible true purpose.

Toma goes head-to-head with Bishop Biagio during an attempt to rescue Agnese. As the battle rages, the Queen of the Adriatic Sea is revealed to be a ship that can completely destroy Academy City.

As the coup continues, even the sisters of the puritan church are targeted, while the queen and princesses find their lives in danger. Index analyzes the evidence of the Eurotunnel blast. Knight Leader is confronted by a former colleague.

Acqua and Knight Leader continue their fateful showdown in the forest. Princess Carissa reveals a devastating new technique using Curtana Original. When Kamijo and Index's lives are endangered, an unexpected ally comes to their rescue.