After the devastation of being cast out of his congregation for a theft he didn't commit, Silas Marner moves to Raveloe, where he keeps to himself on the fringe of society. But at least he can earn a living, and the villagers leave him to enjoy the companionship of his hoard of coins. That is, until one rainy night, he returns home to find his money has been stolen. The theft prompts him for the first time to ask his neighbors for help. A few weeks later, another sort of treasure enters his door: a golden-haired toddler. Silas immediately decides to raise her as his own. This is the beginning of Silas's metamorphosis from miserly outsider to beloved father, good friend, and cherished neighbor.
When readers meet Godfrey Cass, he is fully under the sway of his wayward younger brother, Dunstan. Through blackmail, deceit, and cajoling, Dunstan plays on Godfrey's inability to make a firm decision. The only thing Godfrey is certain of is that he wants to marry Nancy Lammeter. But unfortunately he's already married to an opium-addicted barmaid in another town; they even have a daughter. Hoping that somehow chance will prevent anyone from finding out about the marriage, he continues to pursue Nancy. Chance obliges, and Godfrey's wife dies, but Godfrey is left with an unpleasant choice: claim his two-year-old daughter or marry the woman of his dreams. He marries Nancy, but he is never completely convinced he did the right thing.
Godfrey Cass's barmaid wife, Molly Farren, succumbs to laudanum, a solution containing morphine once used as a narcotic painkiller, and dies in the snow just steps from Silas's cottage. Her little daughter wanders into the cottage, where Silas discovers her golden head pillowed on his hearth. From a mischievous child, Eppie grows into a beautiful young woman. Along the way, she is the catalyst that integrates Silas into the Raveloe community.
From early adulthood on, Nancy Lammeter lives by a strict moral code of her own. Although she loves Godfrey Cass, she knows she would rather stay single all her life than marry a man with a debauched lifestyle. After his brother's disappearance, though, Godfrey changes, and they marry. Nancy is deeply disappointed that the one child they have dies, but she remains a steadfast and supportive wife.
When Silas adopts Eppie, Dolly Winthrop is ready with help and advice, but she never forces it on Silas. Her advice helps him to ensure that Eppie grows up as an integral part of the Raveloe community. As the years pass, Dolly learns about Silas's past, and the two friends share ideas about the nature of God and what constitutes a Christian life. Even if she hasn't read the Bible, she has a clear idea of godliness.
Dunstan Cass is a restless man who keeps himself amused with lies, blackmails, and other intrigues. He relies heavily on his luck to get him out of the scrapes he creates. One night, Dunstan takes refuge from the rain in Silas's cabin. The weaver isn't home, so Dunstan looks for and finds his rumored stash of money. Carrying Silas's heavy bags of coins, Dunstan makes his escape before Silas returns. Unable to see in the rainy darkness, he walks straight into the water-filled quarry—but no one knows. For the rest of the novel, people speculate on where he might be and when he might return. Although Dunstan dies early in the novel, his influence is felt till the end, when his skeleton is found at the bottom of the drained quarry. Alongside it is Silas's money.