September 1st, 1991, 10 am, King's Cross, London

After the orphanage staff had dropped Marcus off with his trunk and his ticket, Marcus made his way to the pillars between platforms 9 and 10 and proceeded to the third pillar of four. Making sure his trunk was behind him, he began to walk straight through the pillar.

Of course, he went through the pillar with a tingling sensation.

In front of Marcus now was a gleaming, scarlet-colored train bearing the logo 'Hogwarts Express'. Around him, Marcus could see men, women, and children—most of them in robes, although there were some in muggle clothing like himself—on the platform. These separate families were hugging their children goodbye, and while Marcus was, of course, happy for them, a slight sense of loss echoed in his heart.

Resolving to deal with his emotions later, he rolled his trunk toward the train and climbed aboard. Since he had arrived an hour before the train set off toward Hogwarts, he decided to find an empty compartment. Along the way, he passed students with ties of green and silver, black and yellow, gold and scarlet, and blue and silver. His own robes, in his trunk for now, were standard black, though he knew that would change tonight.

Spying an empty compartment toward the middle of the train, he opened the door and put up his trunk. However, he pulled out a book he had been reading beforehand,

"A Brief History of Time" by Stephen Hawking.

Eventually, one can only read their textbooks so many times before boredom strikes. So, Marcus had been reading other books to help supplement his understanding of muggle science and physics, which he believed would ultimately be good life knowledge even if it didn't translate to his magical prowess (though he believed it would).

Marcus, engrossed in the words of Professor Hawking, was almost startled when the door to his compartment opened. He glanced up from his book and saw a young girl in plain black robes with bushy brown hair and brown eyes. He had his suspicions about who this person was, but he wasn't sure. Not yet.

The young girl, seeing another person reading and one who she suspected to be a first-year student like herself, was excited to introduce herself.

"Hello! My name is Hermione, Hermione Granger. What is your name? Are you a first-year like me? Do you like to read as well? Wait, is that a book by Stephen Hawking? Are you a muggle-born like me? And—"

Marcus interjected, "Woah, Ms. Granger. One question at a time, please. However, to answer the ones you asked: my name is Marcus Castle, I am a first-year student, yes, I like to read, yes, this book is by Stephen Hawking, and I believe I am a muggle-born, yes."

While Marcus was saying this, he thought to himself, 'It seems my reading this book drew her attention, along with my youthful appearance.'

Hermione, blushing, apologized. "I'm sorry about that, sometimes I get ahead of myself and ask too many questions at once. Do you mind if I sit here with you? Oh, and please call me Hermione."

Marcus replied, "Then please call me Marcus. And you may sit here. Let me help you with putting your trunk up."

Once Hermione's trunk was stowed, Marcus and Hermione sat down across from each other, and Marcus decided to speak first.

"So, Hermione, you said you like to read as well?"

Hermione responded, "Yes! I love to read. I have read all of the textbooks, front to back, at least twice."

Marcus, always impressed by Hermione's talent in academia when reading the books, replied, "Wow. A fellow scholar, I see. Myself, I liked the charms and history textbooks the most. How about you?"

Hermione replied, "Oh, I love them all! I can't choose just one or two. Also, are you an American? I thought Hogwarts only accepted students from the British Isles." She said, just now realizing my accent and being confused by this circumstance.

Marcus responded, "My accent is American, yes. But I am a British citizen, and I live in Islington now."

Hermione asked, "Oh, did your family move to Britain then?"

Marcus, about to answer her, heard the compartment door open. In walked a boy with brown hair and a somewhat pudgy face. He was hauling a trunk and carrying a toad in his other hand. Unfortunately for the boy, his toad jumped out of his hand and began hopping away just as he set his trunk down.

"No! Trevor!"

'Neville Longbottom, hmm,' Marcus thought.

Hermione exclaimed, "Oh no! Your toad is hopping away. We need to find him before he gets lost or hurt!"

Marcus responded, "I may have an idea that will help, but first, we would need to find a prefect. They can use the summoning charm to recall Trevor back to us, I heard about it in passing once."

Neville, having heard his grandmother use the summoning charm before, suddenly looked much better.

"That's a great idea! Thank you!"

So Marcus, Hermione, and Neville found a prefect, and upon explaining the situation, the prefect cast "Accio," and Trevor the Toad was summoned back to Neville. Neville had introduced himself to Marcus and Hermione on the way, and Marcus and Hermione introduced themselves in turn.

Once they were back in their compartment, Neville sitting beside Marcus, Marcus answered Hermione's question from earlier, knowing she was still curious.

"I am an orphan now. The closest thing I have to family is my roommate back at the orphanage." Marcus chuckled.

Hermione, shocked, said, "I'm sorry to hear that, Marcus."

Marcus reassured her and thanked her.

Neville, upon hearing Marcus was an orphan, looked sympathetic due to the situation with his own parents but decided against talking about his circumstances.

And so, Hermione, Marcus, and Neville began to bond as the train whistled and began to leave the station.

A Couple of Hours Later

Marcus, Neville, and Hermione were casually chatting when suddenly they heard a commotion down the hall.

Peering out the compartment door, Marcus saw a boy with platinum blond hair along with two heavyset boys stumble out of a compartment and fall on their behind.

'Draco Malfoy, Gregory Goyle, and Vincent Crabbe,' Marcus recognized.

Deciding that business was handled, Marcus sat back down in his seat. While talking to Hermione and Neville, Marcus wondered how much he should get involved with the 'Golden Trio' and their adventures. Ultimately, Marcus decided he would step in if needed but give the children the opportunity to grow and develop. After all, he still considered himself an adult even though he had been de-aged to the body of a child. He also decided to let canon take its course but to be on the sidelines for the first couple of years while growing stronger and wiser in magical knowledge.

'Sorry, Sirius, but for now, you will remain at Azkaban,' Marcus thought.

Eventually, the conversation drifted to the topic of which house they would like to be in. Hermione said Gryffindor since 'that was the house Albus Dumbledore had been in'. Neville groaned,

"Oh, I'll probably get Hufflepuff."

Marcus, recognizing a chance to boost the kids' confidence, said, "What is wrong with Hufflepuff, Neville?"

Neville responded, "Well, nothing really, but my parents were Gryffindors when they were in school, and I want to follow in their footsteps."

Marcus responded, "Then do so. You may not think you're brave, Neville, but do you know what bravery is? To me, bravery is pursuing what you want in spite of your fears."

Neville was quiet for a minute as he reflected on this, and then gave a small smile and muttered "Thank you, Marcus."

Marcus said, "Anytime, Neville."

Hermione, watching this exchange, was happy to see Neville get a confidence boost but wondered what house Marcus wanted to be in, and so she asked,

"Well, Neville and I both want to be in Gryffindor. What about you, Marcus?"

Marcus, thoughtful for a moment, replied, "Ravenclaw. I would like to be a Ravenclaw."

Hermione and Neville, especially after Marcus' talk of bravery to Neville, were a little surprised and disappointed that Marcus had decided against Gryffindor.

"Why do you want to choose Ravenclaw, Marcus?" Neville and Hermione asked at the same time.

Marcus responded, "It is the house that calls to me the most. I love knowledge and experimenting with it."

Neville and Hermione, still disappointed, understood.

'Plus,' Marcus thought, 'It will allow me to be a more neutral figure in the upcoming conflicts.'

And so, time passed this way, with Hermione stepping out to let Marcus change into his robes, and eventually they arrived at Hogsmeade later that evening.