‘Hey!’ Olympia protested. ‘What do you think you’re doing?’

Abruptly, out in the hallway the fire alarm rang, strident and harsh. Lourds guessed that someone, a student or a professor, had set it off. That had been good. At least all the students would get clear of the situation.

‘Ma’am,’ a man’s voice called from the phone in Turkish, ‘is something wrong? Is everything all right?’

Undeterred, Cleena moved on to the second shelf and began clearing those as well. In the shadowy recesses, the door was hard to see, but Lourds spotted the straight lines. Impulsively, he went to help the woman, wading over and through the books.

‘Thomas?’ Olympia called.

‘Ma’am?’ the Istanbul policeman enquired loudly. ‘Please stay on the line.’

‘There’s a door back here.’ Lourds pulled at the higher shelving.

‘Olympia, you don’t think those men are really here after me, do you? I don’t make enemies like this. They have to be after the book I got down in the catacombs. And if they find out you know something about it, they’re not going to stop at just questioning me.’

Cleena swung round with a shelf and nearly caught Lourds in the face with it. She locked eyes with Olympia. ‘Get over here!’

‘Don’t tell me-’

Out in the hallway, something metallic struck the floor and skidded to a stop near the door. Lourds took in the spherical shape, then redoubled his efforts to get to the door.

‘They’ve got a grenade!’

‘It opens inwards!’ Cleena yelled.

Understanding, Lourds reached for the doorknob but found it lacking. Someone had taken it off. As he turned to Cleena, she shoved him aside with her free hand and fired the pistol three times at the locking mechanism. The bullets cored through the cheap metal and splintered the wood. Before the echoes of the shots died away, Olympia had joined them and the grenade blew up.

The tremendous noise deafened Lourds and vibrated through his body. He expected shrapnel to rip through him, but it didn’t. Bright lights and gas followed the explosion. Flash-bang, he realized. He’d read about those in the novels he consumed during long plane flights and dead time at sites. Those grenades were used to confuse and disorient people.

Cleena grabbed his arm and shoved him towards the door, which still hadn’t opened. Lourds saw her mouth moving but heard nothing. Knowing what she wanted, he set his shoulder to the door and threw his weight against it. The door shivered and sprang open, revealing that it had been covered over by Sheetrock on the other side. Evidently some alterations had been done to increase office space.

The other room was thankfully empty. Lourds didn’t want anyone else in danger or joining their little group. His attempt to open the door ripped it from its hinges and it smashed into someone’s painstaking model reproduction of the Ottoman Siege of Constantinople in 1453. Ships and warriors went flying, followed by the blue waters of the Golden Horn and the fabricated brown coastline.

Olympia followed, almost running over Lourds in her haste. She held the cellphone to her ear, but if anyone was on the other end she apparently couldn’t hear any better than Lourds.

He looked round the room, trying to figure out what he was supposed to do next. They were still on the third floor, too high to risk jumping and breaking a leg.

Olympia grabbed his arm and, when he turned to face her, spoke to him anxiously. He read her lips, missing it the first time because she was speaking her native tongue, not English.

‘Where do we go?’

‘I don’t know,’ he replied enunciating carefully. ‘Up? Down?’

He used his hands in case she couldn’t read his lips. His mouth, eyes and nose all stung from the gas contained in the flash-bang. Tears blurred his vision as he swept his gaze round the room. Two sharp cracks pierced his deafness and he recognized the sounds as gunshots. Anxiously, he peered back into the opening, wondering if Cleena had made it out of Olympia’s office alive.

She barrelled through and hit him full on. Lourds wrapped his arms round her and they fell to the floor on his back. Cleena glared at him as if he were a bumbling moron, which – Lourds reflected irritably – was unfair. He’d been concerned about her. She forced herself up and partially kneed him in the crotch while doing so. Lourds was certain he’d cried out and was glad no one had been able to hear him. Then his thoughts focused on survival again.

Smoke rolled into the room from the grenade. It got harder to breathe. He didn’t know how they were going to get out of the office. They were still in a death trap.

Eckart stood his ground in the hallway with his pistol up. His left hand was wrapped tightly round his right so the semi-automatic pistol’s recoil would respond perfectly and not jam. He peered through the smoke, expecting Lourds and the two women to emerge at any second. The flash-bang held pepper gas as well as the pyrotechnics.

No one came out.

‘Humboldt,’ Eckart called over the com. Three of his men had set up behind him. Three others held the stairs at the other end of the hall. There was no way their target could escape. ‘Set up outside that office.’

‘Yes, sir.’ The man ran forward without hesitation. He wore a mask against the effects of the pepper gas. He waited a moment, then peered round the door.

Two shots rang out in quick succession. Humboldt jerked, then stumbled back. He turned round and clutched at his face, but blood already poured from one of the shattered lenses of his mask.

Eckart cursed. For a home-grown terrorist, the woman was good.

Humboldt staggered twice more, then turned boneless and dropped to the ground. His head rebounded from the floor and Eckart knew the man was dead.

‘Are you sure there’s no other way out of the office?’ Eckart demanded.

‘No, sir,’ Mayfield replied over the com. ‘Two elevators. The stairs at each end of the building. That covers everything.’

Eckart tried to put himself inside the office and work out what he would do if he was trapped in there. You wouldn’t have been trapped in there, he told himself.

‘What about the windows?’

‘The grenade blew the glass out of the one in the office, sir, but the people inside haven’t left.’

‘Can you see inside?’

‘No, sir. The smoke’s too thick.’

‘Keep watch.’ Eckart kept his eyes on the door. ‘How much time has elapsed since the first shots?’

‘Two minutes thirty-seven seconds, sir. We’re coming up on the threshold for this mission.’

Eckart knew they couldn’t stay much longer. The local police would arrive shortly, and the college security armed-response teams had to be en route as well. If they didn’t leave soon, things were going to get messier. He willed himself to be patient. Whatever threat Lourds presented against the United States was about to end. Eckart fully intended to take the professor into custody.

Or kill him.

‘Sevki?’ Cleena cupped a hand over her ear and struggled to hear him at the other end of the earwig connection. ‘I can’t hear. A grenade deafened me.’

‘… other wall – elevator shaft – emergency.’ Sevki sounded as though he was breaking up as he shouted, and she could still barely hear him. But she understood what he was talking about. They’d managed something like this before.

Approaching the wall on the other side of the office, Cleena bent down and took her knife out of her boot. When she reached the wall, she fisted the hilt and drove the broad blade into the Sheetrock. The material gave way easily. Two strokes made an X. She stepped back and drove her boot through it. Big pieces of the material dropped to the floor but others vanished in the space beyond. In seconds, she’d stripped the Sheetrock away to reveal the 2 x 4 studs beneath. She used the knife again to score the wall on the other side. When she kicked this time, her foot went through it.