"Across the Sea" a let down!!!  

It raised a lot of additional questions. Like who was the woman who killed their mother and how did she get on the island. just who built the turning wheel that allows people to leave if the MIB brother didn't get to do it. I still think the MIB is the smoke monster which was created when Jacob sent him into the "light" which was where their "mother" had said to never go. His body was "killed" and his spirit became the smoke monster and that is why he first took on the form of the MIB in the early interactions with Jacob on the beach when Richard's ship came, etc. It did seem rushed and one can only think that if they had the whole thing charted from the beginning that they might have done a better job with it if they hadn't have had the really shortened season due to writer's strike a couple or so seasons ago.

i disappointed too.. it create a lot of question at the end.. hope they ll solve in the upcoming episodes

I think a lot of people are with you on this. More questions arose and less were answered. I think the light is actually the electromagnetism that gives the island its powers, but because of the time that these people were in there really wasn't much science around things. Which also leaves the question of why MIB (Esau) was going to somehow attach the wheel to the light? That just doesn't make sense even though we've seen Ben move it. His explanation for knowing that a wheel needed to be attached was just that "I'm special, I know things" that is the worst explanation they could have given. I'm not really sure if the smoke monster is MIB, I mean his body is gone, but he still is able to take his old form which we've seen when he talks to Jacob, but now he has taken Locke's appearance or body form. I think the smoke monster is still MIB but the electromagnetism changed him into it. I don't understand that part, not sure how the light, or electromagnetism, could do something like that.