Ah: The Last Ritual (Novel)

Aspiring painter Alden Oakes is invited to join a mysterious art commune in Arkham: the New Colony. When celebrated Spanish surrealist Juan Hugo Balthazarr visits the colony, Alden and the other artists quickly fall under his charismatic spell. Balthazarr throws a string of decadent parties for Arkham’s social elite, conjuring arcane illusions which blur the boundaries between nightmare and reality. Only slowly does Alden come to suspect that Balthazarr’s mock rituals are intended to break through those walls and free what lies beyond. Alden must act, but it might already be too late to save himself, let alone Arkham.