Fortunately, the police man has found Dongjoo and Dongwon.  

 Dongtak and Dongok came to pick the children up. Dongok, who was shocked when they were missing, hugs them tight.

When Dongtak and Dongok tries to take them, Dongwon says...

“Did you know that we are not biological son and daughter?”

 Donghui feels heart-broken to hear their conversation.

 When they arrive at home, two uncles are welcoming them.