In the days before the First World War, the measured routine of barrister and accidental Member of Parliament Edward Leithen is disrupted when Charles Pitt-Heron, an Oxford contemporary and now the husband of Leithen's old flame, abruptly goes missing. As he investigates the mystery, Leithen is soon pitted against the murderous forces of "the Power-House," an international network of anarchists, and its chilling leader.