Thanks to their tireless study and discipline, Nanao and her friends are starting to develop a reputation as dependable upperclassmen. Between brawling with a griffin in magical biology and learning harsh truths about the Tir and the Gnostics in their new astronomy course, their workload shows no sign of letting up. Meanwhile, Enrico brings Pete to his laboratory deep in the labyrinth, with Nanao and Oliver secretly close behind. There, the two friends stumble upon a horrifying abyss and get a glimpse of the longstanding conflict between mages and Gnostics. This may be the perfect opportunity for Oliver to finally exact his revenge on the mad old man...!