The plot, set in a village in the fictional county of Loamshire in 1799, revolves around a tangled set of love affairs. The stern Adam, a respected carpenter, is in love with Hetty Sorrel, a beautiful dairy maid; but vain Hetty is in love with Arthur Donnithorne, heir to the local squire; Arther leads Hetty on, but knows that nothing good can come of the affair because of the vast difference between their social situations. Events eventually come to a head when Adam sees the lovers kissing in the woods and confronts Arthur. After forcing Arthur to break off his relationship and leave Loamshire, Adam asks Hetty to marry him. Hetty agrees but, when the date approaches, she does a bunk.
Things eventually resolve themselves when an imprisoned Hetty is visited by Dinah Morris, a Methodist preacher, who encourages her to confront her actions and to repent her sins. Arthur, who has briefly returned, leaves again in disgrace leaving his estates to be managed by Mr Irwine, the rector. Finally Adam and Dinah realise that they have feelings for one another and, after Dinah determines to continue preaching as if nothing has changed, they confess all and get married.
What really struck me about Adam Bede, reading it hot on the heels of some of Eliot's other novels, is the consistency of her moral approach. As in her other novels, she shows that evil does not happen because people have evil intent, but because they are weak and unable to carry through their better impulses.
Thus Arthur loves his tennants, wants to be a good squire to them when his turn comes, and only wants their admiration and respect in as much as he has earned it through patronage; but at the same time, despite his frequent resolutions to break off his damaging affair with Hetty, his moral weakness prevents him from carrying it through. This is particularly telling when, early in the affair he seeks to confess all to Mr Irwine, priest and tutor to him, but fails to do so when he feels that Irwine is pressing on his honour. This contrasts with a similar meeting between Irwine and Adam later on in the novel, when Adam, despite the pain of what he has to confess, shows his greater moral character by pushing on and telling the vicar all about Arthur's relationship with Hetty.
This seems very similar to the way that Eliot allows events to develop in both Romola and Daniel Deronda. In Romola, Tito sows the seeds of his own ruin by refusing to commit to any task that might be difficult and might result in immediate discomfort, unable to see that his decisions will inevitably rebound on him. In Deronda, Gwendolen makes the same sorts of mistakes. Lacking the strength to accept the diminished status of a position as governess to the children of a bishop, she eschews hard work in favour of the apprently easy option: marriage to Henleigh Mallinger Grandcourt, whom she is complacently confident she can manipulate.