Flash forward: We see Sun as one of the Oceanic Six and ready to give birth to her baby. We also see Jin rushing to the hospital with a stuffed Panda Bear, looking like she is going to give it to his newborn baby. We eventually find out that something is not what it seems, but that's just a tease for all of you.
Sun on the Island: After finding out that the people from the ship might not have any intentions of getting them off the island, Sun decides to switch camp. Juliet tries to persuade her otherwise, but to no avail. Juliet then does one of the most unthinkable things. Well, after that secret was revealed, I'm surprised Jin reacted so mildly to it, I suspected mad rage Jin from season 1 or from the flashbacks.
The Boat: We find out what the island is doing to these people who come near it and an old face is seen on the boat. It was mostly boring in the beginning, but once that lady with chains came out, it was just getting good.