Warning: wikipedia contains spoilers
The main story concerns Dorothea Brooke, a beautiful and serious-minded young woman who seeks intelligence rather than looks in a prospective husband. She rejects a titled young man in favour of the Reverend Edward Casaubon, an intellectual middle-aged clergyman who, she imagines, will respect her and value her opinions. This proves not to be the case. After their marriage, Casaubon disdains her efforts to assist him in his research. Meanwhile, she has made the acquaintance of his poor relation, Will Ladislaw. It is Will who makes her recognise Casaubon's shortcomings, both as a husband and as a scholar.
Dorothea's charitable works bring her into contact with Dr Lydgate, whose high ideals are threatened by his obligations to the chairman of the hospital governors. Lydgate falls in love with the pretty but impractical Rosamond; their marriage results in his having to put his financial security ahead of his desire to help others. Rosamond's brother, Fred, an unreliable youth, is in love with the level-headed Mary Garth, creating another sub-plot in this complex story.
When Casaubon dies suddenly, Dorothea inherits his large fortune and tries to use it for the good of others, despite her indignation on finding, in the terms of his will, that she is specifically forbidden to marry Will Ladislaw. In the end, she gives up the inheritance in order to find true happiness with Will.
A highly successful BBC dramatisation of the novel, shown in 1994, had a cast including Michael Hordern, Robert Hardy, Rufus Sewell and Patrick Malahide.