Against her better judgment, Claire Ashecroft agreed to act as a paid beta tester for a new MMORPG based on the computer-guided lucid dreaming (CGLD) tech used by the Phoenix Society to administer the Milgram Battery. Though Mirrored Cage seems innocuous at first, Claire soon finds herself drawn deeper into the game than she'd like. By the time she realizes she's trapped by the dream she's sharing with 10,000 other players, she's lost her way back to the waking world.
Though she can't get out of Mirrored Cage on her own, she's found an exploit in the game that allows her to communicate with the outside world from within the game. Knowing that the exploit will soon be patched, Claire reaches out to her oldest friend, Josefine Malmgren. She warns Josefine to avoid playing Mirrored Cage, but to find Morgan Cooper and ask him to join her in the game.
Josefine seeks out Morgan as requested, and Morgan agrees to help. Before creating his own Mirror Cage account using the invitation code Josefine had gotten from the developers, he tells Naomi and his other friends what he intends to do.
While Naomi and the others research Mirror Cage's developer AlteredState and pierce the corporate veil to learn that AlteredState is a wholly-owned subsidiary of the AsgarTech Corporation via at least a dozen shell corporations, Morgan enters the game. Though Morgan remains in total control of the experience because it's based on the Milgram Battery and he can pierce the simulation, he's not a gamer and not used to navigating the tropes and mechanics endemic to RPGs. While Claire cannot control her dream to the extent Morgan can, she knows the ropes and is able to support him.
Naomi and the others soon learn the secret to Mirror Cage's "compelling experience". The simulation is not generated by an AI. Instead, an AI mines the dreams and nightmares of neurodivergent individuals lulled into working for AlteredState by the promise of a good job in an environment that honors their differences and accepts them for who they are. In-game, these individuals are identified as the Dreaming Gods, and should they wake the game's world would end.
Freeing these exploited individuals requires a two-pronged attack from both the real world and the virtual one. As Morgan and Claire fight their way through to the game's final dungeon to meet with the Dreaming Gods held prisoner by the end boss, Naomi and the others seek authority to raid AlteredState's offices and begin the process of freeing the game's captives.
Along the way, Morgan learns the true purpose of Mirrored Cage. It is not a mere VR MMORPG, but a training simulator for einherjar like him. It teaches einherjar and asuras how to wield their psychokinetic abilities in a safe virtual environment, building up the mental discipline needed to wield these abilities in the real world.
Though Morgan and Naomi are able to get AlteredState shut down and their assets expropriated because the company's exploitation of captive employees, they still aren't able to take down the AsgarTech Corporation or Isaac Magnin.
The novel draws inspiration from "Cage of Mirrors" by Manilla Road (Metal, 1982), which was also covered by Smoulder (Dream Quest Ends, 2020).