Harriet Byron, a woman of beauty and principle, arrives in town at the start of Grandison, leaving behind her two disappointed suitors, the rakish Greville and the humble Mr Orme. In London new admirers spring up. Mr Fowler is so timid that his eccentric Welsh uncle Sir Rowland Meredith must propose to Harriet on his behalf, but the fop Sir Hargrave Pollexfen, struck with her beauty and untutored wit in a sharp debate on languages and learning with the pedant Mr Walden, proposes and is promptly refused. His morals do not suit her, she says. Enraged and insulted, Sir Hargrave abducts her from a masquerade which she had attended out of politeness to friends. Just when all seems set for another Clarissa, Sir Charles Grandison rescues her from Sir Hargrave's coach. Without even drawing his sword, he flips the villain under his own wheels, for as he explains later in a dramatic rencounter with him, he abhors all violence and duels.

Harriet is received at their London home by Sir Charles's vivacious sister Charlotte, a woman who dispenses with the minor punctilios. Out of gratitude and admiration Harriet falls in love with her handsome preserver, the very paragon of a Christian hero: Sir Charles, naturally attracted to another paragon, is mysteriously prevented from declaring an affection that Harriet is frankly prepared to own to Charlotte, to her family, or to disappointed suitors such as Lord D., offered her by his mother.