Nocturnal Academy 11: Tunguska - Nocturnal Academy, #11

For many years the old Siberian Nocturnal Academy was thought to have been destroyed during the great Tunguska explosion of 1908. However, recently the principal of the new Russian Academy, Professor Bukarev, discovered it was actually dragged into the Immaterium by the dark realm's self-styled king, the Demon Lord Abraxas, and languishes there still. Bukarev wishes to undertake a mission to recover the school, its resources, and most importantly, the supernaturals who were taken with it.
But in order to complete this mission, the Demon King must be confronted and destroyed. Professor Abbacus believes Bukarev's mission is doomed to fail unless he accompanies him and his crew. He also decides to bring along his best students; Alice Dibble, Toby Thompson and Carla Hightower. The Siberian Academy lies in the grimmest depths of the Immaterium, and the journey to reach it is long and fraught with dangers.
The school is very old and run-down, filled with defeated survivors who have grown old before their time, and one enormous, completely delusional Demon Lord lording over the squalor like it's the grandest empire in the world. Defeating Abraxas will not be easy, even for experienced mages like Professor Bukarev and Professor Abbacus, and the dedicated students accompanying them. The Demon Lord has scores of followers, including one very familiar supernatural who will do anything to stop his master from being destroyed.
For he alone has discovered the deadly secret that Abraxas is protecting.