The Great War is over and a long-awaited engagement is on, but all is not tranquil at Downton Abbey as wrenching social changes, romantic intrigues and personal crises grip the majestic English country estate. The international hit, written by Julian Fellowes, stars Dame Maggie Smith, Elizabeth McGovern and Hugh Bonneville, with guest star Shirley MacLaine.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.