New York Times-bestselling author Aiden Thomas returns to the beloved world of The Sunbearer Trials in Celestial Monsters, a heart-stopping duology finale, in which three young semidioses travel through a dark monster-infested world, facing down chaotic Obsidian gods, in a quest to save their friends and return the sun to the sky. Teo never thought he could be a Hero. Now, he doesn't have a choice. The sun is gone, the Obsidian gods have been released from their prison, and chaos and destruction are wreaking havoc on Reino del Sol. All because Teo refused to sacrifice a fellow semidiós during the Sunbearer Trials. With the world plunged into perpetual night, Teo, his crush Aurelio, and his best friend Niya must journey to the dark wilderness of Los Restos, battling vicious monsters while dealing with guilt, trauma, and a (very distracting) burgeoning romance between Teo and Aurelio. Determined to rescue the captured semidioses and retrieve the Sol Stone, the trio races against the clock to return Sol and their protective light so order can be restored. Now the future of the whole world is in their hands.