At its heart is Lady Mary Crawley, who is still struggling to recover from the death of her husband Matthew six months earlier.
Neither the devastated young widow, played by Michelle Dockery, nor the viewers have much time to miss him, however. Life at the manor house must go on and a new raft of suitors will vy for her attentions. These include charming Lord Gillingham, an old flame. Shame about the boring fiancée trailing in his wake then.
CLICK ON PHOTO FOR FULL GALLERY OF CASTHer sister Lady Edith has experienced something of a transformation, going from drab to flapper girl fab. Her love life will be rather complicated too since she's entangled with her boss at the newspaper she now works for.
Downton will also get its first black character in the form of jazz singer Jack Ross, played by Gary Carr.
Later on in the series, two real life historical characters make an entrance. The first is author Virginia Woolf, portrayed by Christina Carty, while the second is Australia opera singer Nellie Melba, brought to the screen by Dame Kiri Te Kanawa, the diva who sung at Prince Charles' wedding to Princess Diana.
Downton Abbey is on ITV1 Sunday nights at 9pm from 22 September 2013.