Four people are dead. The coroner signed every one of them natural. Detective Constance Egan knows better, because she was raised by the most patient killer St. Louis ever missed. Three weeks after she put her own father in a cell, Constance is handed a case no one else will touch. Participants in a clinical drug trial at a St. Louis research hospital keep dying of the exact side effect the drug is known to cause. On paper, every death is a tragedy. In Constance's gut, every death is a murder, calibrated so precisely that a clinical trial becomes the safest place on earth to hide a body. No one believes her. Not the hospital. Not the pharmaceutical company guarding a billion-dollar secret. Not the coroner who already closed the files. Only Dominic Akehurst, the FBI liaison assigned to shadow her, a man carrying his own buried grief, is willing to hunt a killer no one will admit exists. But the closer Constance gets, the more the case becomes a mirror. The person behind these deaths kills out of grief, not pleasure, and Constance understands that grief far too well. To catch this killer she will have to think exactly like him. And the only thing more dangerous than a murderer who believes he is right is a detective who is beginning to understand why. She caught the last monster because she is like him. This one is going to make her prove she is not. Trial Dose is the second novel in the Blood Compass series: a slow-burn psychological thriller for readers who love razor-sharp detectives, morally complex killers, and tension that refuses to let go until the final page.