The novel is based on the fact that character is destiny and destiny is character. The logic of cause and effects in the novel are based on the fact that fate and chance also have important roles to play.
Hardy's art of plot construction is unique. He builds the story with minute details. Slight incidents, which are barely noticed, become controlling forces of destiny of characters later. The incidents are in perfect continuity. The novel has a dramatic quality to grip the reader and arouse a feeling of curiosity to know what happens next.
The novel basically can be considered as the biography of the main character Michael Henchard.
The story begins with Michael Henchard, a hay trusser who comes to the village of Weydon Priors where, in a drunken state , he sells his wife Susan and daughter Elizabeth Jane to a sailor Newson for five guineas. When he returns to his senses, he regrets the decision and takes a solemn vow not to touch intoxicants for twenty years.
The story further take a lead of few years. Henchard becomes rich and the mayor of Casterbridge by his hard work. After 18 years his wife returns, Newson than supposed to be dead, she unites to her husband along with her daughter Elizabeth.
Donald Farfrae, a young Scotsman helps Henchard by showing him how to salvage substandard grain he has bought.
But soon Donald Farfrae becomes Henchard rival in both business and love. He marries Lucetta who had formerly been in love with Henchard. The story of the sale of Henchard's wife is revealed and he loses his mayorship. He is ruined in business and takes to drink again and learns about the death of his daughter Elizabeth Jane. His stepdaughter is now his only support but Newson returns and claims her.
Henchard becomes lonely. In the meantime his ex lover Lucetta marries Farfrae but her love affair with Henchard becomes public and she falls into a fit of hysteria and dies.
Farfrae and Elizabeth agree to marry. Henchard comes to attend the marriage but is treated badly by Elizabeth. With a heavy heart he returns and dies after sometime.