Things go badly amiss at Downton Abbey. Robert and Cora are not speaking. The servants are shunning Matthew’s mother, Isobel. And Matthew and Robert have fallen out. Bates takes a gamble. The much-loved cast of Downton Abbey Season 3 includes Maggie Smith, Elizabeth McGovern, Hugh Bonneville, Dan Stevens, Michelle Dockery, Jim Carter, Penelope Wilton, and a host of others.