‘Stay there and don’t move. You try to run and I’ll carve you,’ he said, then put away his knife and rolled up one bloody sleeve.

Polly stared at him, then shifted again.

Ignore all irrelevant distractions. Focus on the target. What was irrelevant? When his hand had closed on her arm, it had closed on the item that she had somehow put on, and which now seemed to be fused to her flesh. The pain he had felt was more than it should have been. Now he stared down in momentary confusion at his hand. His palm had been sliced open and there was a fragment like a thorn of coral embedded in his wrist, blood oozing out around it. She had been getting away. No distraction. He had felt the first shift and how he had been caught at the edge of it and drawn in, somehow, by this lump of material embedded in his wrist. Seeing the leafless trees and drowned landscape, he had for a moment considered the possibility of a memory lapse: one of those blank spots associated with reprogramming. However, his subsequent garbled communication with Operations had confirmed what was real. No one there had heard of his Director of Operations, and no one had heard of Tack either. And by their response to him he just knew they had been sending a kill squad to deal with an anomalous agent—himself.

The girl had done something; moved them. This second time it happened validated his crazy idea about just what she had done. He gazed around and saw that they now stood upon a plain of drying mud, deep with cracks and scattered with growths of sea sage and plantains. There being no trees here, this time, he could see the distant sea wall straddled by a huge slab-facing machine. Nearby the ruins were not clearly defined, mounded as they were with mud and yet to be weathered out of the ground. To his right the thermal generating tower stood tall and pristine, and from it a macadam road led back through the old inner sea wall towards the industrial complexes outside Maldon. People were working in and around the tower, and from it a high-mounted crane was lowering a dismounted generator to a low-loader.

Tack glanced down from this bewildering view and saw he was up to his ankles in the mud. With some difficulty he pulled his feet free. The dry mud was in his shoes, in his socks. The girl was sprawled in the mud and looking as bewildered as he felt, and now Tack realized he must keep her alive. He enjoyed books and the interactives as much as normal people, so he knew about the concepts of time travel, and how leading quantum physicists had stated that it might be possible.

He looked up again to scan their surroundings. The first shift had taken them back to the time of one of the over-floods: two to ten years. This second shift had brought them back to the time just after the new sea wall had been built and the land area enclosed by it reclaimed. Tack had seen documentaries about the furore the project had caused, reclaiming land considered by all insurers as unsafe because of the chances of over-flood—a prediction subsequently proved to be true—and therefore a place deemed by all developers unsuitable for any sort of building. The project had cost millions, and millions more as it had rendered useless many of the thermal towers, which required sea water to operate. And this had all occurred half a century before Tack himself had been a twinkle in his creator’s test tube.

‘It would be inadvisable to go further,’ Tack warned the girl.

She looked at him with her eyes wide, panicky. With slow deliberation Tack squatted down before her, making himself appear less threatening. He wondered if she had any idea what she was doing. He inspected his own injured limb and noted that, even though his hand was still bleeding, the wound in his wrist had sealed around the thorn. Distraction. Trying to exude calm, he rolled down his sleeve and looked at the girl.

‘You go any further back and this place will be under ten metres of sea,’ he told her.

She glanced around then pushed herself upright. Her clothing pulled up dry mud with it; was packed with the stuff. She pulled her blouse out of her pelmet and flat pieces of mud fell out, contoured on one side to her body, as if she had been lying in it as it dried. Tack felt no confusion about this. Land levels change through time, she had travelled, the dry mud had been displaced by her body. It all made perfect sense to him. What did not make sense was why the trees and other parts of the landscape had not been dragged along too. Why her clothes, him, his clothes?

‘How have you done this, girl?’ he asked, expecting no coherent answer—she still looked bewildered, probably not yet grasping what was happening. Certainly all this had been caused by the object on her arm, about which he knew only his DO’s instructions: Come back with it, Tack, or don’t come back at all…

‘My name is Polly.’

Tack considered for a moment. It was always best not to use the name of a potential hit, not to consider them as anything more than disposable. He considered what he should do now: a swift head shot would prevent her doing anything more, and he could next cut the object from her arm. But what then? He had no idea how to operate the thing, and suspected that she was only doing so at an instinctive level.

‘You have not answered my question,’ he said.

‘You’re going to kill me. Why should I?’

Tack nodded and stood up, stepping closer to offer her his hand. ‘You must take us back… you must take us forward again.’

‘Why the hell should I!?’

She rolled and came to her feet, backing away from him. Observing her expression, he was surprised at the sudden intelligence he saw there and realized he had little chance of gaining her trust. There was only one option: he must retrieve the object and learn how to use it himself. Stepping forward, he drew his seeker gun from its chest holster. Momentarily the controls snagged on his damaged clothing. He saw her take a deep breath and close her eyes.

‘No!’

He fired, realizing as he did so that, in snagging the gun, he had switched it back to seeker mode. The bullet shot out, dropping its casing even as it left the barrel, opening its ceramic wings to swerve itself away to one side of her. Swearing, he slapped it back to manual. Then one moment he was sighting on her forehead, and the next moment his lungs were filled with brine.

Water pressure closed over him like a vice and he did not know which way was up. He struggled and he kicked and fought. Breaking the surface, he spewed water and fought for every coughing breath. She was over there, steadily swimming away from him. He knew he needed to stay close, but it was all he could do to stay on the surface and breathe. The sea was rough, rain hammering down, and lightning stalked the horizon. She shifted again, leaving a hollow in the water that closed with a sucking rush. Gone.

With a dogged determination to survive, Tack shed his coat and shoes and swam for the barely visible sea wall—the original that had been well inland after the reclamation. Years of physical training, both when linked to a computer and in the field, enabled him to get to his objective through the cold rough sea, when many others might not have made it. After fighting his way through a mat of bladderwrack, he wearily pulled himself up onto the slabbed face of the wall and coughed dregs of burning salt from his raw lungs. His hand ached and he felt feverish. When he reached to pull the thorn from his wrist he saw that it had spread out into a small hard plate the size of a drawing pin, and was now covered with smaller hairlike thorns, which bloodied his fingers when he tried to pull the thing out. It came part of the way up like a scab, but when he released it to get a better hold, it drew back against his flesh. When he tried again with the tip of his knife, he found he could not move it at all. The thing had now bound itself to the bones of his wrist. He clambered to the top of the wall and looked around, shivering in his soaked clothes.