When psychiatrist Jason Andrews is lured away from Harvard Medical School to spend a year's sabbatical at the Marsden Clinic near Washington, D.C., he anticipates a quiet year of study of the promising new drug Psychoden. Instead, he discovers a gruesome trail of blackmail, suicide, and murder and a national government in crisis.

The Marsden Clinic's clientele is drawn from the capital's most powerful insiders, and as more and more of Andrews' patients fall victim to the mayhem, he begins to doubt himself and all those around him. His efforts to unravel the mystery land him squarely in the middle of the terrifying plot, ultimately endangering not only his own life, but also that of the woman he loves.