Jack, Kate, Locke, and Charlie go on a trip to the spring that Jack found to fill some water bottles. Charlie steps on a beehive and all four of them end up running away after they all get a few stings. Jack and Kate run into the caves and finds two very old decomposed bodies. One is male and the other if a female. Inside a pocket of one of the bodies Jack finds two rocks. One is a black rock and the other is a white rock. Locke calls the bodies the island's Adam and Eve. Later while cleaning some of the wreckage away from the caves Locke tells Charlie he knows who he is. He recognizes Charlie as a member of Drive Shaft. Charlie is happy someone recognized him.
Back on the beach Jin out of blue attacks Michael for an unknown reason and drags him into the ocean where Jin tries to drown Michael. Sawyer and Sayid separate the two and Jin is handcuffed to the axle of the landing gear that is part of the plane wreckage. Michael tells everyone he doesn't know why Jin attacked him. He says he thinks it's because where Michael comes from people like Jin don't like people with Michael's skin color. Later after Walt questions Michael he admits to his son that wasn't really true. Jack informs the rest of the survivors that it is a good idea that they all move to the caves for safety. Some of the survivors argue that some should stay on the beach in order to keep the signal fire burning and to watch for planes and ships.
Unlike the title would suggests, this episodes flashback focuses on Jin and not Sun, although she features prominently in the flashbacks as well. We see that before their marriage Jin was very different towards Sun. Jin is a loving and caring man who is trying to earn enough money so the two of them can get married. Jin asks Sun's father for her hand in marriage. He gives Jin permission to marry his daughter and he also gives Jin a job working for him. This doesn't prove to be the blessing Jin and Sun thought it would be. Eventually Jin and Sun move in together into a rather nice place showing that Jin must be making some good money working for his future father in law. This does come at a price though as Jin becomes a harder and colder man.
Jin, Sun, and Hurley are among the survivors who decide to move to the caves with Jack. Kate surprises Jack when she tells him she is staying at the beach. Also staying is Sawyer, Michael, Sayid, Claire, Shannon, and Boone. At the cave Locke tells Charlie he knows about his drug addiction. Charlie gives Locke the stash of drugs he has. Locke goes off on a ramble about the island giving something to Charlie that he really wants but he has to give something up first. I dunno, then he tells Charlie to look up. Locke has Charlie believing the island made a trade: the drugs for his guitar which is hanging in some vines above the cave opening.
We see Jin come home, in his flashback,
covered in blood. He goes straight into the bathroom with Sun following
close behind. She is worried but Jin tells Sun the blood isn't his.
Sun doesn't like the man Jin has become and she makes plans to leave him
at the airport in Australia. Ultimately she cannot go through with it
though and turns her back on the car that is there waiting to help her
make her getaway. As they check in at the airport Jin gives her a
flower just like the flower he had given her when they first started
dating years ago.
Back on the island we see Michael have an awkward run-in with Sun. Michael is shocked to learn that Sun can speak English. She also tells Michael that Jin doesn't know she can. Sun tells Michael Jin attacked him because he is wearing Sun's father's watch. Michael says it means nothing to him that he found it in the wreckage. Michael goes back to the beach with axe in hand and gives Jin the watch back. Then he uses the axe to chop through the chain on the handcuffs freeing Jin.