The story is told by a minor townsman looking back on a season of disaster, and it opens far from any conspiracy. It begins with Stepan Trofimovitch Verhovensky, an aging liberal of the 1840s who has spent decades posing as a persecuted thinker while living comfortably as the dependent of the wealthy widow Varvara Petrovna. This older generation of harmless, vain idealism is presented as the soil from which the harder generation grows.
Into the town come the two figures who will tear it apart. Nikolay Stavrogin, Varvara Petrovna's handsome and gifted son, returns trailing rumors of strange cruelty and a secret marriage to the crippled, half-mad Marya Lebyadkin. He has the power to fascinate everyone and the will to commit to nothing. Around him orbit men who took their convictions from him years ago: the suicidal philosopher Kirillov, the fierce convert Shatov, and the engineer of chaos, Stepan Trofimovitch's son Pyotr.
Pyotr Verhovensky builds a small revolutionary cell, a quintet, and works the town's officials, intellectuals, and ladies into confusion. He plans a grand local fete, spreads scandal, and pushes events toward a breaking point. In a long night walk he lays his vision before Stavrogin: shock, slander, the leveling of all talent into a herd of equal slaves, and a hidden, beautiful figurehead, Ivan the Tsarevitch, around whom a legend can be built. He admits he is not really a believer in any of it.
The fete collapses into farce and then horror. Fires break out, Stavrogin's wife and her brother are murdered, and a town worker dies. To bind his cell together with shared guilt, Pyotr arranges the killing of Shatov, who wants to leave the group, staging it so the suicide-bound Kirillov will take the blame in a written confession before shooting himself. Kirillov does die by his own hand, after one last argument about God, will, and freedom, but the murder begins to unravel almost at once.
The ending scatters the survivors and judges the ideas through them. Pyotr escapes abroad while the weaker conspirators break down and confess. Stepan Trofimovitch wanders off and dies, and on his deathbed he reads the Gospel passage about the devils driven into the swine and applies it to Russia: the sick man will be healed once the demons are cast out. Stavrogin, asked at last to be saved by a woman's love, finds he can believe in nothing and feel nothing, and he hangs himself, leaving a note that says no one is to blame.