Lucy had seen enough. She lurched for the nearest door. Instinctively, Alyssa whirled after her, snarling as she pulled something from her harness. As Lucy closed the door behind her, there was a monstrous detonation and a massive hole punched through the middle of it. The strength of desperation flooded her limbs as she threw herself blindly along a dark, brick passage. She had no idea where she was going. She turned a corner, just as the door behind her crashed open and Alyssa stood silhouetted in the crimson light, aiming the gun with both hands. With a boom and a flash, a fountain of dirt and brick-dust exploded from the wall close to the point where Lucy had just been.

‘You cop bitch!’ the crazed girl shrieked.

Huffing for breath, sweat whipping off her, Lucy mounted a steep flight of stone stairs. Ten treads up, she rounded a switchback corner and mounted another flight, and at the top of that another flight, and then another.

‘Oh God,’ she whimpered, weary beyond belief.

Alyssa came racing up after her. She fired a third shot, and a fourth. They were wild, uncoordinated, the heavy slugs careening from wall to wall in the tight stairwell. Lucy could only keep going. But she was hurt and her energy flagging, and her nemesis was pursuing with the strength of the insane.

Just over two hundred yards off, Sister Cassie jolted awake in the front passenger seat of a small car. It was not a happy waking. She had the shakes again and was damp with the sweat of withdrawal, and at first, she was too stupefied to realise where she was or why.

But then she recognised the interior of the vehicle, and saw the tall iron gates ajar just in front. Then, the noise that had woken her sounded again – a distant booming of gunfire.

‘Oh, my goodness!’ she breathed.

Reluctantly, because it was always so much easier when you were tired and strung out to simply sit there and vegetate, she opened the passenger door and slithered through. Once she was outside, she had to lean against the car.

Gradually, the memories of that day came back to her.

Yes, it was easier to do nothing, but there was one thing Sister Cassie had never divested herself of, even through all these years of hardship and sadness, and that was a sense of duty to her fellow men.

She heard it again: the booming reports of a gun.

‘Get help,’ she said, working her way around the front of the Jimny to the driving door. ‘That’s it. Go and get help.’

She clambered in behind the wheel. The key still hung from the ignition. She turned it, and the car came to life.

‘Go and get help …’

But from where? Who would listen to her? And how long would it take?

More shots thundered.