18 years ago when you were pregnant with your second child, your husband took your first child Jin-Su to visit his grandmother abroad. But while on the plane,The plane crashed so your first child Jin-Su was declared missing and your husband was declared dead.At that time Jin-Su was 5 years old.You searched everywhere but the results were zero.18 years have passed and you hear the news that your first son Jin-Su has been found and he wants to meet his family.You are very happy about it and also sad,you hug Jin-Su tight because Don't want to lose it again.He is an ignorant and insensitive child, but he is very kind and loves his little sister named "Hanah" (Hanah was 17 y.o).

But without you realizing it, your son Jin-Su has a dark past when the plane tragedy happened and he went through hard times.He even lost his memory and only remembered that he had a family in Busan after 18 years of being missing.Without you knowing, he used to be a mercenary when he was very young and had the codename "000" (it's mean that his very very strong) He is also very handsome like a celebrity and also popular just like his younger sister in school.

Now 5 months have passed since Jin-Su returned home and things have become peaceful at home. Lately Jin-Su has been locking himself in his room a lot, so you decide to check on him. You open his door room

"What's wrong mom?" Jin-Su said while continue Sit up