The novel opens with Zarathustra descending from his cave in the mountains after ten years of solitude. He is full of wisdom and love and wants to teach humanity about superman. Arrive in the town of the Motley Cow and announce that the superman must be the meaning of the earth. Humanity is only a bridge between animal and superman and, as such, must be overcome. Superman is someone who is free from all prejudices and morality of human society and who creates his own values and purposes.
People on the whole seem not to understand Zarathustra and not to be interested in superman. The only exception is a tightrope walker who has fallen and dies shortly after. At the end of his first day among the people, Zarathustra is saddened by his inability to move this "herd" of people into the market. He decides not to try to convert the multitudes, but rather to speak to those individuals who are interested in separating from the herd.
Most of the first three parts consist of individual lessons and sermons given by Zarathustra. They cover most of the general themes of Nietzsche's mature philosophy, albeit often in highly symbolic and obscure form. Appreciate the struggle and the hardships, as the path to superman is difficult and requires great sacrifice. The struggle against the superman is often symbolically represented as climbing a mountain, and the free and carefree spirit of the superman is often represented through laughter and dance.
Zarathustra is sharply critical of all kinds of mass movements and of "rabble" in general. Christianity is based on hatred of the body and this earth and an attempt to deny them both by believing in the spirit and in the hereafter. Nationalism and mass politics are also means by which tired, weak, or sick bodies try to escape from themselves. Those who are strong enough, Zarathustra suggests, struggle. Those who are not strong give up and turn to religion, nationalism, democracy, or other means of escape.
The culmination of Zarathustra's preaching is the doctrine of eternal recurrence, which states that all events will repeat themselves again and again forever. Only the superman can embrace this doctrine, as only the superman has the willpower to take responsibility for every moment of his life and want nothing more than every moment to repeat. Zarathustra finds it difficult to face the eternal return, as he cannot bear the idea that the mediocrity of the mob will repeat itself for all eternity without improvement.
In part IV, Zarathustra gathers in his cave a number of men who approach, but who do not quite reach the position of superman. There, they enjoy a party and a series of songs. The book ends with Zarathustra joyfully embracing eternal recurrence and the thought that "every joy wants deep, wants deep eternity".
