On a quiet morning in California, a lone gunman opens fire on a busload of children headed for a field trip, then turns the gun on himself. Forensic psychiatrist Leander Heartwood and special agent Gabriel Chin team up to investigate the case, seeking at first only to solve this single disturbing crime but in time delving into issues of race, morality, and the complex forces at work in all horrifying acts of violence.Part mystery, part psychological thriller, part piercing social commentary, Equation for Evil is a riveting and incisive meditation on violence and the nature of evil.