The designers spend months building whole new worlds, then tear them down as though they never were when filming is over. Just like a breakup, only more physical and less damaging. Sometimes it’s hard saying goodbye to the characters I become. I spend so long with them that they start to feel like family, perhaps because I don’t have a real one. My anxiety levels are at an all-time high by the time the buggy turns the final corner. I haven’t rehearsed for today the way I normally would, there just wasn’t time. The traffic of worrying thoughts has come to a standstill in my mind, as though it were rush hour up there, and I’m stuck somewhere I don’t want to be.

We stop outside our final destination: an enormous warehouse that contains most of the interior film sets for Sometimes I Kill. I hesitate before going inside. My mind is so full of everything that is happening in my private life that for a moment I can’t even remember what scene we are shooting.

“Good, you’re here. I need you to deliver something special today, Aimee,” barks the director as soon as he sees me. “We need to believe that the character is capable of killing her husband.”

I feel a little bit sick. It’s as though I’m trapped inside a life-size joke.

I stand on the set of my fictional kitchen, waiting for my fictional husband to come home, and I see Jack smile at me before our first take.

Nobody is smiling by the twentieth.

I keep forgetting my lines, which never happens to me. I’m sure the rest of the cast and crew must hate me for it. I get to go home after this scene, but they don’t. The clapboard sounds, the director says, “Action,” again, and I do my best to get it right this time.

I pour myself a drink I’ll never swallow, then pretend to be surprised when Jack comes up behind me, slipping his arms around my waist.

“It’s done,” I say, turning to look up at him.

His face changes, in exactly the same way it did nineteen times before. “What do you mean?”

“You know what I mean. It’s done. It’s taken care of.” I raise the glass to my lips.

He takes a step back. “I didn’t think you were actually going to do it.”

“He wouldn’t give me what I wanted, but I know that you will. I love you. I want to be with you, nobody else is going to get in the way of that.”

The word “Cut” echoes in my ears, and I can tell from the look on the director’s face that I’ve nailed it this time. As soon as he’s watched the scene back, I’ll be free to go.

I’m chatting to Jack outside in the sunshine when the golf buggy reappears in the distance on the lot. I don’t think anything of it at first, just carry on talking about the time frame for postproduction. But then my eyes find something familiar about the shape of the woman being driven towards us.

This cannot be happening.

Detective Alex Croft is wearing a smile wider than I thought her tiny face could support. The vehicle comes to a halt right in front of us and she climbs out, beaming. Her unsmiling sidekick jumps off the backward-facing rear seat, smoothing down his trousers as though sitting down has caused an upsetting crease.

“Thank you,” Detective Croft says to the driver, “and thank you,” she adds, in my direction.

“What for?” I ask.

“I have always, always wanted to drive around a film studio on a buggy, and now I have! All thanks to you! Is there somewhere we can talk?”

“This is a closed set,” says the director, joining us just when I didn’t think things could get any worse. “I don’t know who you are, but you can’t be here.”

She smiles. “This is my badge and it means that I can. So sorry, I forgot to introduce myself with all the excitement and stardust. My name is Detective—”

I read the questions on Jack’s face without his having to say a word.

“I’m sorry, they’re here because of a personal matter. I’ll deal with it,” I interrupt, and wait for the others to walk away, out of earshot. Jack keeps throwing concerned glances over his shoulder, and I smile to try to reassure him that everything is okay.

“Did you have to come here?” I ask when I think nobody can hear.

“Is there some reason why you didn’t want us to?”

“You could have called.”

“I could have, but then I wouldn’t have got to see all this. You’re probably used to it, but for me, well, this is like a trip to Disneyland. Not that I’ve been.”

“What do you want?”

“I think the first question most people in your situation might ask would be ‘Have you found my husband?’”

“Have you found my husband?”

“Sadly no, we have not, but I need your help with something. Is there somewhere a little more private where we can talk?”

Her face lights up like a Christmas tree when we step inside my dressing room.

“There really are lights around your mirror and everything,” she says, beaming.

“There really are, yes. You said you needed my help.”

“I did. I think we might have got ourselves in a muddle when you gave us your statement, for which I can only apologize. We work crazy long hours, and sometimes we make mistakes.” She takes her iPad from the inside pocket of her jacket. “I had down that after leaving the restaurant, you came straight home, went to bed, and went to work the following morning, presuming your husband had spent the night sleeping in a spare bedroom.”

“That’s right.”

“Except that we didn’t have a note of you going for a drive in your husband’s car.”

“You don’t have a note of me doing that because I didn’t.”

“Really? Sure looks like you…” She turns the screen to face me, before using a small, skinny index finger, with a short, neat nail, to swipe between images. “I mean, I appreciate that the image is a little grainy, compared with what we got from the restaurant, but that looks like you parking his car at the petrol station, and that looks like you paying at the till. See, we only had the credit-card receipt, and I think most people would assume someone was buying petrol. I know I sure did, and this is why I need your help because, according to the records, this woman—the one driving your husband’s car and using his card, the woman who looks a lot like you—well, she wasn’t buying petrol. She was buying several bottles of lighter gel, like the stuff you squirt on a barbecue if you have an impatient personality. So … are you certain that isn’t you? On the screen I mean, I don’t need to know whether you’re impatient.”

I stare at the woman in the photo wearing a coat that looks just like mine, with dark curly hair resting on her shoulders, and oversized sunglasses on her face. “No, it’s not me.”

“It does look like you. Don’t you think it looks like Mrs. Sinclair, Wakely?”

“I thought so.”

“Have you looked into the woman who was stalking me? The one I told you about?” I ask.

“Why? Does she look like you?”

“Yes. I’ve never seen her close up, but she used to dress like me and stand outside our old home.”

“Do you know her name?”

“I already told you, no. At least not her real name.”