SEASON FINALE: Season 5 ends tonight with an expanded finale, with PBS importing and coupling both the end-of-season episode and the subsequent, year-ending Christmas special. It’s loaded with surprises, satisfying plot culminations, and even an appropriate holiday miracle of sorts. The beauty of Downton is that its characters are so richly delineated, this sort of extended storytelling becomes its own reward. One teaser I will reveal: Matthew Goode, who has been so charismatic on both The Good Wife and in The Imitation Game, reveals his smiling charms again as a new visitor to the Abbey, and the newest guy to be in orbit around Lady Mary (Michelle Dockery). Check local listings.