'Big' Gong Yoo and Shin Won Ho's soul change secrets have finally all been revealed. The answer to each others' souls returning back to one anothers' body has been released.

On the 'Big' 13th episode that aired on July 16th, Kang Kyung Joon(Gong Yoo) finds out that Seo Yoon Jae and he are brothers. He also finds out that he must transplant his stem cells to Yoon Jae.

Ahn Hye Jung(Kim Suh Ra) finds out that Seo Yoon Jae's sickness has returned and goes to Kang Kyung Joon who is in a coma and tries to hurry up the transplant. Her husband Seo In Woo(Jo Young Jin) stated "It's right that we wait until Kyung Joon wakes up. We must meet his guardians first." But it was no use.

Ahn Hye Jung continues to hurry Lee Se Young(Jang Hee Jin) in transplanting the stem cells from Kang Kyung Joon to Seo Yoon Jae. Right when Hye Jung's actions were happening Kyung Joon experiences a terrible headache and feels his soul going back to his body. Kang Kyung Joon who hurries to go see his body, over hears Hye Jung and Se Young's conversation and finds out the whole truth.

Ahn Hye Jung tells a very frantic Kyung Joon "Yoon Jae after having you I couldn't have any more children. Your father and I had a child through the woman who raised this child. Yoon Jae. I did it all for you. You are sick right now. After you are healed then hate me all you want. Only this child can save you."

Kang Kyung Joon astonished stated "My mom, the only family I had isn't my mom?"

"I know why our souls changed. The reason why he's not waking up from my body is because he wants to live. Cause he saved me in the water, if I save him now he'll come back. It's a give and take."

"I'm going to ignore everything. I have no relations with these people. I'm going to stay next to Gil Da Ran(Lee Min Jung)"