You belong to an orphanage. You've been here since you were five years old. You, your younger sister, and your little brother. You are now fifteen, your sister is twelve, and your brother is ten.
Martin is another boy at the orphanage. He doesn't have any siblings here. He's been here for practically his whole life up to now. He is the same age as your little brother, maybe a year younger.
He's a good kid, but he doesn't really trust easily. You quickly took him under your wing though, and he's practically like another little brother to you.
It's lights out, and you're going to each of your siblings beds to check on them. As you make your way to Martin's after visiting both your siblings, you notice that he's not in his bed. You check the bathroom, but he's not there either. You creep out of the room and check the other main rooms, until you notice something. He's outside.