For a three-act plot analysis, put on your screenwriter’s hat. Moviemakers know the formula well: at the end of Act One, the main character is drawn in completely to a conflict. During Act Two, she is farthest away from her goals. At the end of Act Three, the story is resolved.
Act I
In Act I, Silas is evicted from Lantern-Yard, settles down in Raveloe, and begins to hoard his money. Act I kicks off the story with a gruesome death and a dastardly theft, both of which seem like they'll introduce a much more action-packed book than they actually do.
Act II
In Act II, both of our so-called heroes rather pathetically sit around waiting for something to happen, if only they knew what they wanted. Silas can't even respond to his friendly neighbors, and Godfrey just fantasizes about a hearth full of Nancy's children. Only the little toddler Eppie is capable of any kind of action: she toddles into Silas's house and, predictably, warms the old miser's heart.
Act III
Silas Marner's Part 2 begins Act III. Sixteen years later, Eppie is all grown up, Silas is part of the community, and Nancy and Godfrey are married but childless. The major event of Act III is the discovery of Dunstan's body, which catalyzes the revelation of everyone's secrets—except the secret of what really happened at Lantern-Yard. Dun dun dun.