Maggie clenched her teeth and felt her circulation thud in her throat. He’d almost reached them. Maggie pointed at Holly’s breath that was escaping in clouds. She sealed her mouth. The footfalls halted then sped up and changed in pitch.

He was climbing the steps to the door. They heard the handle and then it swing open and shut. Maggie exchanged a look with Holly.

There was no need for discussion. Keeping her attention on the smaller building, Maggie hesitantly followed his deep footprints up the steps towards the navy blue entrance. No movement in the windows opposite. Holly was close behind. Maggie put her palm on the cold metal of the handle and pulled it down. As she cracked the door, a draught of warm air and the concentrated smell of cooked meat gushed out.

Beyond was a changing room. A row of plastic white overalls were hanging on hooks. There was no sign of the man who had just entered. Maggie hastened inside. The sooner they were off the front steps the better. Holly carefully clicked the door shut behind them.

Maggie nodded to the next blue door that led out of the changing room and crossed the grey tiled floor to it. Holly tapped her on the shoulder and pointed at the overalls. Maggie nodded again, and they took one each off a hook and briskly slid them on.

The overall was thin and smelt strongly of plastic. As they paused by the door to listen for any sounds, Maggie noticed a box of white elasticated hats that looked like shower caps. She handed one to Holly, and they both donned them before Maggie depressed the handle and peered outside.

They edged into a long corridor with more blue doors along it. Some open, others closed. They passed the first and could see it was a communal area. There was a coffee machine, microwave and lots of dirty paper cups scattered over a low table surrounded by plastic chairs.

Where had the stocky guy disappeared? There were another six doors either side of the corridor. Maggie tried the first and was looking into a unisex bathroom.

A slam from the end of the corridor. They waited, motionless but nobody emerged from any of the doors so they made their way cautiously to the last one. Maggie tugged it.

She was looking down a short corridor to a large set of blue double doors. Another warm gust and they could hear machinery rumbling. Pushing through them they were confronted by an expansive high-ceilinged room, silver pipes ran across its girders and there was a tall bank of chrome industrial food processors before them. No sign of the stocky guy or anyone else.

‘Let’s try and find cold storage.’ Maggie led the way through two large grinders. If they ran into anyone it was unlikely the overalls would sell their presence there. There were no other workers around. They covered the polished white floor, passing several huge silver canisters that vibrated deep in her chest.

There was a sign hanging over the next piece of apparatus. Maybe it could point them in the right direction.

But as she squinted at it a figure turned into their walkway. It was the stocky guy, minus his hat and coat.

He stopped dead. ‘Who the fuck are you two?’ His few strands of dark hair were plastered to his scalp.

‘Night shift,’ Holly answered immediately.

‘Bullshit. How did you get in?’ His beady eyes darted, and he loped forward again.

Maggie immediately pulled her gun.

‘Jesus.’ He froze and raised his hands as high as his chin. ‘If you’re cops you’d better have a warrant.’

‘Anything you want to tell us?’ Maggie wondered if he had any colleagues nearby.

‘Let me see the warrant first.’ He put out his hand.

Maggie noticed it was shaking. ‘You seem very nervous.’

‘You’re pointing a gun at me.’ But he was examining the weapon in her hand and frowning. ‘You ain’t cops.’

Holly pulled out hers.

‘Easy,’ Maggie cautioned her.

‘What is this?’

Maggie clocked a security camera in the ceiling above him. ‘The only relevant fact is that we’re holding the guns. Just take us to cold storage.’

‘What?’ But a brief spark of panic registered in his gaze.

‘You heard me.’ Maggie took a pace towards him.

‘There’s no cold storage.’

‘We don’t have time for this,’ Maggie snapped. ‘You’ve got three seconds to do it or we’ll find somebody else.’

‘I’m the only one here.’

‘Liar.’ Maggie knew somebody had let him in. ‘Do it now.’

But Holly was suddenly choking beside her before an arm locked around Maggie’s neck. She struggled but, as the solid bicep cut off her oxygen, her vision went gradually yellow then quickly black.