They criminalized his mind. Now they need it to survive.

Victor Eastmore has mirror resonance syndrome, a cognitive difference that his society considers a disease and polices like a crime. So-called Broken Mirrors are classified, medicated without their consent, and sometimes permanently institutionalized. Victor has spent his life afraid of losing his mind and freedom.

In Toxic Medicine, the fateful final installment of the Resonant Earth queer science fiction quartet, Victor is rising through the ranks at his family's company, BioScan, even as it faces bankruptcy. Then a cure arrives in the form of a brain implant gifted by the Diamond King, a synthetic consciousness obsessed with bringing humans into its empire. Every mind the Diamond King heals is a mind it can rule. The Organized Western States have already been colonized by the Diamond King's totem spawn. The rest of the American Union of Nations, and Europe with it, are readying for a war none of them are sure they can win.

Victor believes in the cure, which makes him a traitor to the movement resisting the brain implants. But he also has a plan to finish the research his murdered grandfather began. Jefferson Eastmore cured cancer and died before he could do the same for his own grandson. Victor pursues that work alone, in secret.

Caught between a cure he believes in and the allies who question his judgment, Victor must choose. Will he take the Diamond King's implant and be made well on its terms or gamble on a dead man's unfinished work?

Toxic Medicine blends psychological sci-fi, political intrigue, and emotional depth in a thought-provoking conclusion to the Resonant Earth quartet, a story about stigma, isolation, and who gets to decide when a mind is well.