Right, let's get this out of the way right from the off - The Yukine story arc has to be easily the weakest of Clannad ~After Story~. There, I've said it now.
After the misunderstanding last episode which caused the rival gang to thing that Sunohara was Yukine's brother, things were only ever going to get worse, and indeed this turns out to be exactly the case. Despite Yukine's attempt to mediate, the two gangs appear to be headed on a collision cause that will only end up involving the police and probably worse, although she does at least manage to tone things down to a one-off fight between her "brother" (to be "played" by Sunohara) and the leader of the rival gang.
This seems like a simple enough idea, until Nagisa turns up with some of her mum's latest invention, "rainbow bread" (thankfully not available in all good supermarkets) which knows the whole of Kazuto's gang out cold, as well as Sunohara in the process. So, Tomoya steps up to the plate to fight the rival gang leader, in a scrap which lasts a surprisingly long time considering we mostly see Tomoya getting his ass kicked. Just as all hope appears to be lost and all-out gang warfare is about to break out, so Kazuto Miyazawa appears... Or does he? Of course not, he's actually dead (which was made about as obvious as it could possibly have been last episode without explicitly saying so), and Yukine is in fact simply pretending to be her brother in a desperate last ditch attempt to stop the fighting.
I'm not sure what it is about this story arc, but the last couple of episodes of After Story have singularly failed to grip me in any way, shape or form - The whole thing seemed dull, plodding and contrived, and aside from at least getting to see a little of Tomoyo (which is always a treat) there was little in the way of redeeming features about this episode much like the previous one. Still, I remain confident that things can only get better from this point onwards, and the episode nine preview seems to hint that we'll be moving towards the real crux of the After Story plot, so with any luck we'll get some real improvement over the coming episodes after a couple of not so stellar story arcs.