To Nina and Eddie’s relief, the other route beyond the junction led deeper into the complex. They entered a wider corridor that curved away into the distance. ‘It’s got to be this way,’ said Nina, panting. The wail of alarms faded behind them. ‘And we’re clear of the gas; now we’ve just got to—’

An echoing gunshot – and a red-hot spike tore through her left arm.

Eddie whirled to see Wintz in a doorway a hundred feet away. He snapped off a shot, forcing the mercenary back into cover.

But they were completely exposed in the stark concrete passage. ‘In here!’ he shouted, pushing Nina to a nearby door. Another bullet impact blasted stinging cement fragments at his head as they rushed through.

The new room was a large archive, tall shelving racks filled with countless white-spined hardback volumes. Nina crashed against the long shelves, clutching her wounded arm. ‘I’m fine,’ she gasped.

‘Let me see.’ She winced as she lifted her hand. There was some blood, but the bullet had only clipped her. ‘It’ll need treating, but you’ll be okay. See if there’s another way out, I’ll hold him off.’

‘Eddie—’

‘Just go!’ He returned to the doorway, watching for Wintz—

The mercenary was already running towards him.

‘Shit!’ Eddie threw himself back as more bullets slammed into the door frame. He loosed a couple of suppressing rounds to force the other man to swerve, then scrambled away from the entrance. ‘He’s coming! Is there another exit?’

Nina ran down the aisle, reference volumes flicking past on both sides. She reached its end – and found the wall ahead was an unbroken barricade of books. ‘Oh, crap!’

‘I’ll take that as a no!’ He heard motion outside and sent another shot through the doorway. A thump and a grunt as the other man flattened himself against the wall.

That gave him a few extra seconds. But he had nowhere to go, trapped in the archive. And the rising cry of alarms warned that the gas was still spreading. If Wintz pinned them down until it reached the door, they were dead . . .

He had to take the mercenary down, fast – which meant drawing him into the archive. He shouted at the top of his voice: ‘Nina! Get out of that back door, now! I’ll be right behind you!’

Praying she wouldn’t instantly blow his ruse by yelling ‘What back door?’ he ran a short way, then used the shelves as a ladder to climb onto the top of the stack. The ceiling was mere claustrophobic inches above him. He slid over so Wintz wouldn’t see him when he entered, then waited. Faint steps outside – then the mercenary darted through the door.

Eddie glimpsed the top of his head as he swept his gun from side to side, seeing no sign of his prey. Wintz hesitated, then headed deeper into the archive.