Eighteen-year-old champion VR gamer Arthur Trewe is a "debugger": an operative sent to corrupted private virtual game worlds to exfiltrate trapped users. Direct-to-brain VR technology has become so immersive that safeguards are necessary. In servers called black shards, such protections have been stripped away. This allows players to experience the full range of sensation, including pain and suffering, while also exposing them to brain damage or even permanent brain death.

Lately, a series of such black shards have been corrupted by "dreamers" – malicious AIs that possess the game's story-core. The only way to free users from such worlds is to infiltrate them as a player. Once inside, Arthur must play along and stay in character to avoid "waking" the core until the players have been rescued. Then it's time to face the dreamer.

After the deaths of several human operatives, the company deploys next-generation AI agents known as "daemons". These AIs are so effective at hunting down dreamers that they're put in charge of debugging missions. Yet they still need humans to guide and protect them. Arthur isn't thrilled to be babysitting his own potential job replacement, but he has to admit that Mantis, his AI partner, is smarter, funnier and – depending on her mood – more charming than he is. Charming enough that, between missions, he finds himself spending more and more time with her in VR worlds of their own rather than dealing with his own very real problems.

At the rate his peers are dying, he tells himself he doesn't mind being replaced by AI – as long as he qualifies for a Gold Level career performance bonus first. Yet when a series of black shard missions gone awry raise troubling questions about the nature of the dreamers and the games themselves, Arthur is forced to make a choice between what's left of his career as a VR operative, his growing feelings for Mantis and uncovering the truth at the heart of the rogue story-cores.