Shelter

Sungjae and Changsub are siblings who grew up with their grandma as their parents were separated when Changsub was very young. Their father left the country and married someone else. They moved to their grandma's place as their mother was working. But then their mom passed away when Changsub turned around 10 yrs.

Also, Age gap may not be exactly 4 years, I can be more maybe around 5 to 5.5yrs or whatever fits the storyline :)

I got my inspiration from Ask in the box when one of the questions to Changsub was "What would you do if Sungjae was your real younger brother" and of course, I had to take into consideration, his answer to this question.

Also, the same Story is updated in AO3 so, it is not plagiarised. I am the same person there. hehe