Lost Episode 2.16 The Whole Truth

When Sun starts feeling nauseous and dizzy, she takes a home pregnancy test to learn that she is in fact, pregnant. But instead of being happy about the news, Sun looks conflicted, and we find out why through her flashbacks...

...which tell the story of a time in Sun and Jin's relationship when Jin wanted desperately to conceive a child, hoping it might bring an end to the constant pressure put upon him by Sun's father, while Sun was off taking English lessons from Jae Lee and planning her escape to America.

Since they haven't had any luck conceiving, Jin suggests that they visit a fertility specialist. The specialist tells them that Sun has endometriosis and that their chances of conceiving are impossible, news that clearly upsets Jin more than it does Sun.

Sun confesses to Jae Lee that she feels relieved about not being able to conceive and confides that she was planning on leaving Jin for America. And while their relationship is that of teacher and student, it's clear that Jae Lee would like it to be more when he encourages her to stay in Korea with him.

Back on the island, Sun finally tells Jin that she's pregnant, to which Jin reacts with pure joy. But Sun has one last thing to reveal in the final flashback we learn that the doctor lied to Sun and Jin out of fear of the Paik family, assigning the problem to Sun when in fact it is Jin who is sterile.

Sun swears to Jin that she has never been with another man. Jin accepts her word and declares that the pregnancy must be a miracle. Tears of joy roll down his face, but the look on Sun's face tells us that we can't be entirely sure we've heard the whole truth

Meanwhile, Locke enlists Ana Lucia's help in interrogating Henry, against Jack's better wishes. But Ana Lucia is able to accomplish something none of them have she earns Henry's trust and gets him to draw her a map to the location of his alleged balloon crash. Feeling betrayed that Jack wasn't the one to tell her about Henry, she enlists the help of Sayid and Charlie to go out and find the balloon.