Spoilers ahead for the earlier volume.
As in, it opens with Akira level-grinding alone in the labyrinth. Learning things. And not entirely alone.
And, with his effective exile, the story splits. Tsukasa decides to leave the castle because of what he's learned, and six of the summoned students go with them. One of them recounts how he probably broke the curse on the six of them, sleepwalking.
More worldbuilding is revealed, and bits of the plotting going about them.