But Simon became more withdrawn as the hours and days went by. He stared at something crawl across the brickwork, something only visible to him. His pale complexion was clammy, his T-shirt drenched in sweat, and he became sick, as if whatever writhing phantoms he saw on the walls had made him ill. Curling up on the floor, he seemed to go into a kind of trance.

Jerry came into the room every day to throw food on the floor, little more than scraps. He waved the knife and warned them all to stay back, those orange lenses swinging angrily around the gloomy basement as if he was deciding which of them to kill first. Maybe it was just her imagination, she prayed it was, but Karin thought his gaze lingered on her. When Becky tried to tell Jerry that Simon needed a doctor, he ignored her. Slamming the door behind him, they heard the lock snap into place.

On the fifth day – or it could have been during the night, it was so difficult to tell – Becky sat beside Simon on one of the rough blankets as he shuddered with a fever.

‘What can we do to help?’ she asked him.

‘I’m s-sorry,’ he said through chattering teeth.

‘You don’t have to be sorry about anything. But we’re worried about you, Simon, we need you.’

‘The walls.’ His voice was faint. ‘Please… the walls.’

She leaned closer. ‘I can’t hear you.’

‘I can’t be here… in this place.’ He grimaced in pain. ‘It’s th-the walls, they’re too close, I can’t b-bear it.’

Karin watched Becky stroke Simon’s arm and felt a shameful burst of jealousy. He was in a bad way, she saw that, but Karin needed Becky’s comfort too. Just because she wasn’t ill or crying her eyes out every two minutes didn’t mean she wasn’t petrified; she needed her friend’s love and attention just as much. And she didn’t like to think about the way the man called Jerry kept looking at her…

Paul was sobbing again, and Lydia looked over and made a face at Becky. We need you. Paul was often hysterical with tears, and the last thing they needed was for him to start screaming. If he did, maybe Jerry would make good on his threat to kill them. Becky wearily climbed to her feet and walked over to crouch in front of him.

‘Everyone is going to be so happy when you get home,’ she told him.

‘You don’t get it,’ he wailed. ‘My father is going to be angry!’

‘Of course he won’t, he can’t wait for you to come home!’

But his face crumpled with misery. ‘He’s going to be so mad.’