We edge round until we can see the set properly. It’s the interior of a library, and two actors are sitting on armchairs. The lady is all dressed up in a velvet crinoline, and the man is in a tailcoat. Bending down, talking to them intently, is a skinny guy in jeans with bright red hair.

“That’s Ant, the director,” murmurs Don. As we’re watching, Ant leaps back to his chair, puts on his headphones, and stares intently into his monitor.

“Rolling!” yells someone from the set.

“Rolling!” several other people echo at once. “Rolling! Rolling!” Even behind us, by the door, two girls are yelling, “Rolling!”

“Rolling!” I join in helpfully. “ROLLING!”

This is so cool. I feel like a member of the film crew already!

“Action!” calls Ant, and, like magic, the whole place becomes totally still. Anyone who was walking has stopped dead, and all conversations have ceased, mid-sentence.

“Kidnapped,” says the lady in velvet. “Kidnapped!” The man takes hold of her hand and she gazes at him mournfully.

“Cut!” shouts Ant, and leaps down onto the set again.

“This scene is set in the home of Lady Violet,” whispers Don. “She’s just learned that their daughter Katriona has been kidnapped by pirates. Would you like to go closer?”

We tiptoe forward till we’re at “video village.” There are several director’s chairs with names printed on the backs of them, and I look at them lustfully. I would die to have a chair with my name on it. My mind is suddenly seized with an image of a chair reading: BECKY BRANDON, WARDROBE DESIGNER. Just imagine if I started working in movies and I got my name on the back of a chair! I wouldn’t ever want to stand up. I’d walk around with my chair stapled to me.

The wardrobe designer on this movie is called Renée Slattery. I’ve already Googled her and planned what I’ll say if we meet. I’ll compliment the costumes in Saw Her Too Soon, which is another movie she worked on, and then I’ll talk about the challenges of working with period dress. (I don’t know much about that, but I can busk it.) And then I’ll ask casually if she needs any help, maybe with shopping for grosgrain ribbon, or button boots, or whatever.

I mean, she’s bound to need help, surely? And then we can start working together and bouncing ideas around, and I’ll edge myself in that way.

Both Suze and I are given director’s chairs with VISITOR written on the back, and we perch self-consciously on them, watching as they shoot the scene twice more. I can’t actually tell the difference between the takes, not that I’ll admit that. Ant keeps swigging coffee and staring into the monitor and shouting instructions to some guy with a high-up camera to the left.

Suddenly he swivels round and stares at Suze and me, then says, almost aggressively, to Don, “Who are they? What are they doing on my set?”

Don ducks his head down and I can hear him murmuring, “Lord Cleath-Stuart … financier … special guests … studio …”

“Well, keep them out of the way,” says Ant brusquely.

Honestly! We’re not in the way! I roll my eyes at Suze, but she has found a script from somewhere and is reading through it, mouthing lines to herself. Suze would really have loved to be an actress. (Or an eventer. Or an artist. Or a newsreader. She’s had lots of career ideas, to be honest.)

“Dylan!” The director suddenly raises his voice. “Where’s Dylan?”

“Here!” A mousy guy in a gray T-shirt hurries forward.

“This is the writer,” Don explains to Suze and me. “He stays on set in case we need extra dialogue.”

“We need another line here for Lady Violet,” Ant is saying. “We need to convey the gravitas of what’s happened but also, like, the dignity of Lady Violet. She’s not going to buckle. She’s going to fight.” He pauses. “Only in, like, three or four words.”

“Right.” Dylan is nodding anxiously. “Right.”

As Ant strides away, Dylan starts scribbling on a yellow legal pad, and I watch him in fascination. He’s creating a film, right here. We’re watching film history being made! Then suddenly an idea comes to me. It’s so good, I almost gasp out loud.

“Sorry,” I say, waving to get Dylan’s attention. “Excuse me. I don’t mean to interrupt, but a line came to me, and I thought you could use it. It just popped into my head,” I add modestly.

“Well done, Bex!” exclaims Suze.

Dylan sighs. “What is it?”

“ ‘With great power comes great responsibility.’ ” As I say it out loud, I can’t help feeling proud of myself.