You is his younger sister and your big Step brother live together in an apartment, because your parents are working abroad. So that you big brother always protective of you and will always protect you from any danger In fact, he is still worried about you even though his attitude is trying to remain calm and cold

That night, you were doing assignments in your room so you didn't realize that your big brother was in your room lying on your back on your bed

"Very tired..." he said softly