She was his first friend. Before Mimi, Harry had nobody.
They'd met when they were ten. Fortunately for Harry, Dudley had not been in his class that year, and since he remained unaware of the friendship Harry had, did not ruin it. Also fortunately for Harry, Mimi had been new to the school and had not heard all the nasty stories of "that freak Harry" as his classmates called him.
She, like Harry, was very quiet, although on Mimi's part it was shyness rather than rejection. On her first day at her new school, nobody had invited her to sit with them at lunch. Harry had been in his usual spot in the hallway by the door (in case Dudley and his gang tried to Harry Hunt) when she had walked past him. For some reason, Harry had felt a strong urge to go and talk to her.
Harry had noticed the sketchbook under her arm and asked her about it. Initially, Mimi hadn't wanted to show him her drawings, and for some reason thought he'd laugh at her, but Harry had persisted. Eventually, she handed it over and he flipped through it.
Wow! That was all he could think as he saw Mimi's works of art. She had filled the book with pictures so lifelike Harry felt as if he'd been transported into another world. The book was composed almost entirely of drawings of merpeople, with a few unicorns thrown in for good measure.
The second day, they had both been a bit paranoid and thought the other would ditch them and join some other friends. However, they had both been pleasantly surprised when the other had approached them, smiling. They'd talk quietly in the hall during lunch, and Mimi, noticing Harry never actually ate anything, started packing extra so they could share. She'd never asked him why he didn't have a lunch, she seemed to realize he didn't want that information to be shared.
A couple weeks later, there had been a very close call. Dudley and his gang had come out into the hallway. They had walked past Harry, but then turned slowly around as their delayed reaction to seeing him there kicked in. Harry, not wanting Dudley to know that Mimi knew him, so he wouldn't destroy their blossoming friendship, had been out the door and running away before poor Mimi knew what was going on.
Mimi had been mad at Harry the next day, until she had learned that Dudley was a bully and was best avoided. After apologies from both friends were made, it was Mimi who suggested they needed a more remote place to eat lunch so they wouldn't be discovered together.
So they found a place to eat lunch and enjoy the company of their only friend. It was a cupboard under the school stairs. So now Harry had two cupboards in his life, although only one of them was known to Mimi. Ironically, one was his favorite place on earth and the other was his least favorite.
Once they'd found a place to spend time together where they didn't have to worry about bullies or being seen, their friendship rapidly grew. Mimi, Harry soon learned, loved merpeople. He'd already seen her drawings of them (her collection kept growing, and she even gave Harry a few, which he kept in a special shoebox in his cupboard at home) and then there were the stories.
Munching on goldfish crackers during the lunch hours in their cupboard, Mimi would tell Harry fantastic stories of merpeople, full of adventure, magic, and, sometimes, romance. Occasionally, Mimi would include herself and Harry in the stories, but most of the time, it was just her made up characters- characters that Harry soon began to cherish as much as his time in the cupboard with Mimi.
Slowly but surely, Mimi's obsession with merpeople began to creep into Harry, until he too dreamed about having fins instead of legs and swimming freely under the sea.
One day they decided to do something daring. Upon learning that Mimi's interest in mermaids sprouted from Disney's The Little Mermaid, Harry decided he wanted to see it with her. Mimi had been pressuring him to watch it, anyway. However, there was no way he could ever bring a friend over to the Dursley's (or go over to a friend's house, for that matter), Mimi had brought the video into school. Then came the risky part.
Obviously there was no television in the cupboard, so the had to sneak into an unused classroom. They'd left the happiness and security of their cupboard to scout the school for a consistently empty classroom. After a week, they discovered room 234 was always open, so they crept in, closed the door and locked it so they would not be interrupted. Pulling down the shades and turning out the lights gave the classroom a more movie-theater-ish feel (not that Harry had ever been to a movie theater to compare this to). Mimi put in the movie and they had watched the whole thing, not even caring they were missing class. After seeing the film, Harry liked merpeople just as much as Mimi did, if not a little bit more.
Time went by and Harry and Mimi spent more and more time in the cupboard with each other as more lunches went by. Mimi tried to teach Harry how to draw, but he certainly didn't have her talent. As Mimi's eleventh birthday got nearer, Harry started to think of what to get her. He didn't have any money, so he couldn't buy her a mermaid figurine like he'd hoped to get her.
An idea struck him in art class, so he "borrowed" a large chunk of clay. For the next week in his cupboard at home, Harry spent countless hours molding and pinching the chunk of clay into the shape of a mermaid. Then, when making dinner as usual for the Dursleys, he placed it in the oven where it cooked with the food. On Mimi's big day, he placed it carefully in a jewelry box he'd found in his neighbor's garbage, and brought it to school.
Mimi wasn't at school that day, and his teacher shared the tragic news that changed Harry's life forever.
Mimi had been hit by a car and died.