As Petra watched, it became clear that Beccie was on a short, regular loop. Nod, turn to the left, rub right thigh, nod, wipe right cheek… Nod, turn to the left, rub right thigh, nod, wipe right cheek… and repeat.

Why wasn’t he seeing it? If she could just snap him out of it, make him see what she was seeing.

Petra knocked on the glass and it reverberated with a heavy, dull thud rather than the hollow sound she’d expect from a window. ‘Vincent,’ she hissed, aware of her voice carrying in the concrete tube. ‘Vincent!’ Now louder, hammering at the window.

He turned to her.

‘That’s not Beccie. Can’t you see?’ She beckoned in case he couldn’t hear – Come out of there. Come home.

But his eyes didn’t find her. He scanned the window for a moment before turning back to Beccie. A one-way mirror, perhaps. Blended into the fake rocks of the fake cave, Petra made out a doorway behind Beccie. A little way down the corridor, she found a turning that led to the entrance, on this side painted gunmetal grey. In the orange dust thickly layered on the cold, hard floor at its threshold, scuffs of several footprints tracked in and out.

Petra pushed at the door and it resisted heavily, but when she pushed the handle down and shoved with her shoulder, it grated open, an obstinate arc forming in the grit at her feet. From behind, the projection of Beccie was even more rudimentary, clearly made to be viewed face to face. The blue stripes in her sweatshirt seemed to run out of pigment halfway around her back, fading into an obscure silhouette against the bright objects and hidden sconces in the bright Aladdin’s cave. Her hair, tied back in a ponytail, was roughly imagined, and her jeans and red sneakers were unpatterned and unlabelled.

Vincent didn’t seem to notice her as she walked in and he carried on talking to Beccie. Petra strained to listen.

‘I knew it was you, Bec. I would never leave you alone.’ He put his hands out towards her, pleading for her to take hold of them, to come into his arms.

She spoke back. While some of her words had the tone and rhythm of English, with some clearly recognisable words included, Petra couldn’t make out the meaning. ‘There is no kotoba ni shoto for shyurta hodo.’

Vincent paused, mid-stride, wanting to believe that he was seeing what he so desperately wanted to. ‘What did you say, honey? What does that mean?’

He waited for an answer that didn’t come, but all Beccie did was cycle through her ritual: nod, turn to the left, rub right thigh, nod, wipe right cheek. Vincent tried again: ‘Beccie?’ Now he spoke to the walls, the low ceiling of the cavern. ‘Is there something you want to say to me?’