Disclaimer: I don't own Harry Potter, I do own the aforementioned characters, and the story idea.
Albus Percival Wulfric Brian Dumbledore was the first to see a young boy walking towards Hogwarts School of Witchcraft and Wizardry on a sunny Friday. He didn't recognize the boy as one of his students, but the boy being able to get past the force field was a sign he could be a young wizard. He didn't appear old enough to be a Hogwarts student, he seemed to be around 10. Albus peered around his office in worry. If the Ministry had found this young boy on Hogwarts grounds, the school would surely be under questioning. Caring more about the young boy than the Ministry, Dumbledore greeted him at the door before he could even attempt to knock.
"H - Hello..." the young boy stumbled, astonished.
"Hello, Blaine, is it?" the boy nodded, wondering how this old man could possibly know his name. The man began walking at a rapid pace, Blaine forced to follow, "My name is Albus Dumbledore, or as you may call me, Professor Dumbledore. I am the headmaster here at Hogwarts, a school, that you'll find, is unlike any other that you may have been to. Tell me, has anything weird happened to you outside of this school lately?" Blaine wondered if he should tell "Dumbledore" what had happened to his friends. Seeing that he was kind to Blaine, and had almost seemed to anticipate his arrival, Blaine decided to tell him. He told him first of the old building that appeared to be in ruins, how when they had gotten closer to the school, his friends had all been pulled by some force by their ankles off the ground and couldn't walk past that mark, but he could, and as he did, he saw the school exactly as it was inside the force field.
"Yes, yes..." Dumbledore appeared to be thinking as he stroked his beard for what seemed like a century, "Blaine... Does anyone in your family have any unusual talents?"
"I-I don't know."
"Alas... It's curious that you found it before you're even of age... What shall we do?" Dumbledore appeared to be talking to himself more than Blaine, so he just tried to keep up with the headmaster's pace. The walls were a fast blur, he couldn't look at any long enough to see pictures, or doors. Dumbledore said it was a school, but he didn't see any students. Maybe they were in lessons. They arrived at what appeared to be their destination, an empty classroom, no students, no pictures hanging, there was nothing special about the room at all, really. It was just a normal classroom.
"Blaine, at this school, we do not teach subjects that you see in everyday schools. We don't have a gym class, we don't teach classes on World War 1, we don't have classes which teach you to use silly 'electronics.' Our school teaches students how to handle the special abilities that they have been given. Abilities that many people in this world don't believe exist. Blaine, do you have any idea what this school could teach you?"
"Magic?" Blaine replied questioningly.
"Now Blaine, what makes you think that? Why not... Underwater basket weaving? Has anything strange happened to you that you think this school would explain logically? Of course, maybe what happened to your friends, although, that could just be a force field, they're very prominent before full moons."
"No, sir, it's not just that. There have been..." he thought how he could explain it, "other things. Things that don't happen to my friends, or my family. Sir, I think you know more than anybody what I would be talking about. I know this is a school of magic."