Part one of the drama is set in June/July 1842.
Mary Smith (Lisa Dillon) flees a crisis at home in Manchester to stay with two spinster sisters, Deborah Jenkyns (Dame Eileen Atkins) and Matty Jenkyns (Dame Judi Dench), in the small, rural town of Cranford. Deborah is the dominating force in Cranford society, and the kind-hearted and eccentric Matty believes her to be the best judge in all matters.
A new young doctor, Frank Harrison (Simon Woods), is brought to Cranford to join Dr Morgan (John Bowe) in his medical practice. Despite Dr Morgan talking up his protégé, the mere fact that Frank is a young bachelor and trained in London is enough to make him the talk of the town.
When the town's carpenter, Jem Hearne (Andy Buchan), has a catastrophic fall from a tree, Dr Morgan is horrified to learn that, instead of amputating the injured arm, Dr Harrison is determined to attempt new and risky surgery. Everyone gets involved in the case, and gossip and rumours spread, led by the unassailable Miss Pole (Imelda Staunton).
Meanwhile, Cranford's reigning aristocrat, Lady Ludlow (Francesca Annis), who lives two miles outside Cranford at the splendid Hanbury Court, wants to turn her attention to the planning of her annual garden party with her trusted estate manager, Mr Carter (Philip Glenister).
The Jenkyns are intrigued when the house across the street is let to a retired soldier, Captain Brown (Jim Carter), his daughter Jessie (Julia Sawalha), and Jessie's ailing older sister.
Deborah and Matty are riveted to see that he seems acquainted with another local aristocrat, Sir Charles Maulver (Greg Wise), who engages the Captain in an unknown business proposal.
Further episode synopses are available in Network TV Programme Information.