Herzog is alone, now that Madeleine has left him for his best friend. Solitary, in a crumbling house which he shares with rats, he is buffeted by a whirlwind of mental activity. People rumoured that his mind had collapsed. But was it true? Locked for days in the custody of his rambling memories, Herzog scrawls frantic letters which he never mails. His mind buzzes with conundrums and polemics, writing in a spectacular intellectual labyrinth. Is he crazy, or is he a genius?..