The lawyer has just left and Matthew gives Isobel the lowdown: Lavinia's father didn't wish to divide his estate, so when Lavinia died, he made a new will with three possible heirs of whom Matthew was the last in line. The first one died before Lavinia's father (of the same Spanish flu epidemic that killed Lavinia), but the lawyer thought the second would be easily found. However, it turns out that he fucked off to India to visit some land he owned there and hasn't been heard from since; moreover, the value of the estate is astronomical -- far more than Matthew ever would have thought, given Lavinia's father's fairly simple way of life. Well Matthew, you're the one who keeps telling people to simplify. As shocking as it is, maybe someone actually listened to you!
Thomas has just flat-out refused to dress Branson; Mrs. Hughes appeals to Carson, but he won't hear of it either, so Mrs. Hughes is like, all right, then it's Alfred's big chance! Carson sniffs that Alfred wouldn't know what to do "beyond collecting dirty shoes outside the door!" Mrs. Hughes replies that he'll just have to learn and when she's gone, Carson looks at Thomas, who merely shrugs. Honestly, I'm surprised that Thomas doesn't want to get a look at an undressed Branson, but his pride does seem to push aside just about all other considerations.
At dinner, things are off to a bad start with Branson as he's not in evening wear, prompting the Dowager Countess to ask if it's an Irish tradition not to change for dinner. Branson explains that he doesn't own tails or a dinner jacket, prompting Lord Grantham to cut in that he hopes Branson at least owns a morning coat, being that he's there for a wedding. Branson, unbowed, says he does not have that and Sybil chimes in that they lead a completely different kind of life. Lord Grantham sniffs, "Obviously," and being this toffee nosed would look bad on him normally, but given his ruinous financial situation, I have to say for one of the first times that he really needs to shut up. Mary, far more civilized than her father, suggests that Branson buy a Downton wardrobe and leave it there so he won't be bothered with carrying it for visits. Edith pipes up with her approval, but Branson declares that he can't turn into someone he's not just to please them. Isobel, of course, supports that notion and Matthew likewise tries to keep things civil by... bringing up Irish politics. I can adore Matthew and still think he's not the sharpest knife in Mrs. Patmore's drawer, right? Branson replies that Ireland is "in sight of throwing off the English yoke," and Isobel asks Branson what he thinks of "The Act" (the Home Rule Act that divided "South" Ireland and North Ireland). Branson, shockingly, isn't a fan and when Matthew and Isobel try to parse his discontent with Home Rule, he asks, "Would it be a problem for you to be ruled by the German Kaiser?" At this, Carson literally breaks the glass he's holding at the stem, and if Sybil winces because she doesn't think things can get any worse, she might want to save something for the next dinner we see. Lady Cora, probably less attached to the British monarchy than anyone else there, changes the subject by asking Branson if it's true that Irish gardens have more variety than those in England. Edith takes up the conversation topic and while Branson doesn't have much to say on the subject, he does at least sit there without decrying the British oppression of Irish flowers.