While critics were able to sneak a peek at Downton Abbey’s fourth season during TCA, there’s now a trailer for all of us to enjoy. The just-released video opens with Mary mourning the death of Cousin Matthew, but soon spins into a whirlwind of dancing, laughing, crying, kissing, tea-drinking, and general dinner-having over the sounds of Joy Formidable’s “Wolf’s Law.†Does the song mean Edith’s modernity will rub off on the rest of the house? Will this really be her year? What will happen with Mary’s future suitors? And just who is the new nanny? There are so many questions ahead of the January 5 premiere (including “When do we get to see Paul Giamatti?â€) and nothing to do but watch this preview several dozen times.