Jack knows I want him to go, but I can see in his eyes that he is sad.

“OK, fine. You can come in for a minute,” I say, feeling Bella listening carefully to every word I say, “and then—well, then yes, you can bugger off. I’ve got, like, a whole painting to finish and you know I’m not very sociable when that happens. Only Humphrey can come anywhere near.”

Jack laughs. “You spoil that cat.”

Then it’s raining again, so we run the last bit, hand in hand, up the hill to my house. We run past a woman with long tangled hair who’s struggling to put up an umbrella, and a man pushing a bike with a toddler on the back. The toddler waves at us and shouts, “I gettin’ wet!”

I wave back with my free hand and feel Bella in the other, gripping Jack, trying to use her powers to electrocute him, wishing he would die because he is normal and happy and she doesn’t think that’s fair.

Jack is not really normal and happy, but he is, compared with Bella. I love him. Everyone thinks he’s my boyfriend, but he’s not: he’s better than that. We have a thing that works for both of us.

I don’t want a real boyfriend. I don’t think I’ll ever want a relationship. My school is a posh girls’ school, but a lot of the sixth-formers live in a world in which they defer absolutely to boys. It’s pathetic and it makes me mad, but I haven’t been brave enough to say anything, because that would draw more unwelcome attention. Actually, if I tried to argue with them, Bella would jump out and smash the nearest simpering handmaiden with the closest fire extinguisher, so it’s probably best that I bite it back.

Jack likes the best side of me, which is the only thing he sees. Hanging out with me has helped him in all sorts of ways, and for a while he raised my status so I was not a top-level target. But that didn’t last long, and soon after, the girls at school started on me again. I don’t really know why they do it, except that I’ve always known I don’t fit in. I expect the girls who are mean to me don’t feel they fit in either, and probably they’re using me to make themselves feel better. I don’t know. All I know is that I am not widely liked, and that feels like shit.

I’ve never told Jack about the things that happen to me at school. He would only get upset and mad, and nothing would change, apart from him being a little less happy. And I want Jack to be happy. Only Lily, my other best friend, knows what happens, and Lily protects me from it as much as she can.

When we burst in, Mum is standing in the hallway, pretending she just happens to be there, holding something in her hands and smiling in smug anticipation.

I look at it. “My phone!” I say, and she grins and holds it out to me.

“Someone handed it in,” she says. “The police called and I picked it up. It restores your faith, doesn’t it?”

Mum is just saying that because it’s a cliché: she doesn’t need her faith restored. She’s not disillusioned or cynical about anything, though she does make sure to keep me as safe as she possibly can at all times, from dangers that don’t actually exist. I take my phone from her and quickly check it; everything’s exactly as it was when I last saw it yesterday morning, just before I lost it in town.

I don’t think Mum has looked through it. I hope she hasn’t.

Bella is inside my head, clearing her throat, demanding attention. I push her aside.

Mum doesn’t look as if she’s had a shocking insight into my school life. She is happy to see us, Jack and me. She lives for us. She stands around in the hall waiting for me to come home because I am her life. It’s weird. Obviously it’s nice, but I do feel bad for her, because her life must be boring. Sometimes I try to imagine my way into her head, and I just can’t. I don’t think she has a dark side at all.

She would be so upset if she knew the truth about me. That’s why I can never tell her. Right now Bella is knocking on the inside of my skull, and I need to get away.

As soon as we are through the door, Mum clicks all the locks shut behind us. No house is quite as secure as ours.

For as long as I can remember, keeping me safe has pretty much been Mum’s career. She is compelled to make sure I am always safe—always, always safe, all the time. It’s almost funny that she relaxes when I’m tucked away in my bedroom, considering the fact that it’s actually the danger zone.

Jack is grinning back at her.

“How are you, Mrs. Black?” he says in his polite way. “You’re looking lovely.”

She loves that. Mum adores Jack. She wants us to get married and give her lots of grandchildren. Again, she has no idea that that can never happen, which is sweet. I say nothing, because Bella is in my head and I can’t talk very well at the moment.

“Cookie?” she says. “I’ve just made some. Still warm from the oven.”

I’m not going to stop to have a cookie, but I’ll save some for Bella because she might like them later. Unless they’re the spelt-and-sweet-potato ones Mum made last week, too, in which case no one will ever, ever want one.

“No, thanks,” I say.

“Yes, please,” says Jack at the same time. He’s hoping for the chocolate chip cookies, I know it.

While he follows her into the kitchen, I walk straight ahead and go into the bathroom and close the door and lock it and lean against it and try to breathe. I have to get rid of them both. I have to make Jack go home in the next few minutes. My head tightens. Black spots dance across my vision.

He is sitting at the table, flirting with Mum. They both do that. I think Jack finds it funny. God only knows what Mum is up to. She grins at him and looks coquettish and reminisces about her youth, and he laughs in all the right places and says the right things back to her. Neither of them particularly cares whether I’m bothered when they do this, and although it’s gross, I just roll my eyes and look away.

I hear Mum say the cookies are ginger and sultana. That’s just about acceptable, so I do my best to clear my head. I unlock the bathroom door and try to act normal, taking three cookies and wrapping them in a paper towel.

“Sorry, Jack,” I say, and under Mum’s approving eye I walk over and kiss the top of his head. “Got to do some painting. See you tomorrow.”

He laughs. “Sure. See you tomorrow, Ells. I won’t hang around.”

“You’re welcome to—” Mum starts to say, but I silence her with a glare and leave the room, gasping for breath, taking the stairs twoat a time.

I close my bedroom door and try to breathe. My head is ringing so loudly, I wouldn’t be able to hear anything else, not even a fire alarm or a nuclear siren if it went off. Maybe one of those things is happening right now. But I don’t care if it is. I roll up my sleeves and look at the tiny lines on the insides of my arms. I’m ashamed of them. I’m never going to let that happen again. They are so small that only I know they’re there.

Be nice, I say to Bella.

BE NICE, she replies, imitating me. BE NICE. ALWAYS BE NICE.

Oh, please stop.

PLEASE STOP. PLEASE STOP. PLEASE STOP.

Leave me alone.

LEAVE ME ALONE.

Leave

me

alone.

LEAVE.

I don’t know what is me and what is her.

I put my hands to the sides of my face and scream silently like the painting. All I want is to be normal.

I draw in a shuddery breath and press the palms of my hands on the carpet, feeling the floor, being here in this moment, myself in my room. One thing I have learned over the years is how to pretend, and when this door is closed, I don’t have to pretend anymore. It can all come out.

I pull the pictures out from under the bed. They are meticulous explosions of horror. They are filled with death and maiming and nightmares. Bella drew them, and she likes to look at them. Perhaps I can assuage her with them.

I call her Bella because she is the dark side of me. It’s Ella but not. It’s Bad Ella. Bella. I gave her a name a few years ago and that made it a bit better, because before that I called it the Monster. Anything is a tiny bit better when it has a name. Bella is better than the Monster. I didn’t know then that Bella means “beautiful”: my Bella isn’t beautiful at all. She is the opposite. But she’s still Bella.

Bella is desperate to own the whole of me: as Ella, I am alert and battling all the time. Sometimes I have to let Bella out before everything explodes. That’s when she draws these pictures. It’s scary, but after that happens, I feel calm and peaceful and, I think, kind of happy. Everything is balanced for a while. I look at the drawings now. They are done in black ink—huge sheets of tiny detail like Hieronymus Bosch, but with modern bits in them. Children are decapitated here. Body parts are everywhere. There is blood and murder. These pictures take us ages and I hope no one ever finds them, but they’re definitely the best art I’ve ever done.

But today is different.