Equation Nineteen is a suspense thriller set in the prestigious medical community of Boston. Its two main characters are Pete Peterossi, a detective on the Boston Police Department, and his father, Doctor Gerry Peterossi, a world-renowned research expert in the field of Alzheimer's disease. Pete is called to a suburban Boston location to investigate a bizarre murder scene in which a mysterious substance appears to have transformed the behavior of many of the party's attendees. Federal authorities are called in as well and they quickly try to dismiss Pete from any further involvement. Pete continues his investigation using back channels and comes to the realization that the mysterious substance may be the byproduct of his father's Alzheimer's research team. Meanwhile, Gerry knows that his team is on the verge of a medical breakthrough and now must wonder if some of the research has been used for unintended consequences. His life becomes further complicated when he is asked to work on a secret government research project that he is told is related to his Alzheimer's work. Both father and son must keep their investigative efforts confidential but both also have a need to divulge their secrets to each other. Over time, it becomes apparent to them that they are working on reverse sides of the same issue and that both of their lives are in jeopardy.