‘You can always come back,’ Sophie replied. ‘Really, I feel we ought to be paying you for the work you’ve put in. Has everybody got their mail in the bag? Good, I’ll lock it then. Don’t forget to pick it up, Luke.’

‘When have I ever?’

‘There’s always a first time. Especially when your mind’s on other things. I’ll be down the coast today, Matt, so if anyone rings for me, ask them to call back tonight.’

Matt’s brown gaze fixed on her. ‘You expecting a call then?’

Sophie shrugged. ‘Be pointless trying to guess. I’m just saying – in case.’

At the camp, Tilly unloaded the day’s supply of wood, then drove to Connor’s camp only to find his vehicle missing. Disappointed beyond reason – after all, she had only wanted to report the missing box in the cave – she drove back to the ablution block and set about the day’s chores. Once she had hauled off the ashes, she walked down to the river to start the pump, but after anxious moments with her ear pressed to the delivery line – ‘Always be sure the water’s actually running, or you’ll burn the pump out,’ Luke had instructed – she switched off the solar-driven pump with a heartfelt ‘Damn!’

‘Now what?’ The pipe was definitely empty. Could the foot-valve be jammed open? She eyed the opaque face of the water, corrugated into ripples by the wind, and visions of crocs filled her mind. No way she was setting foot in that! What would the boys do? she wondered. Well, for a start they’d know how the system worked. She only knew it by rote.

Hands on her hips, she considered the matter. The pump floated on a raft, which was tethered to a post planted firmly in the sloping bank. If she were to pull it closer, she could step onto the raft and maybe raise the foot-valve to investigate it without entering the river, but what then? How did you get water back into the line? Because, as far as she could see, the lack of it was the root of the problem. The action of the pump pushing the water along the pipe opened the foot-valve to drag more in, according to Luke. Only air in the line would stop it, in which case you had to bleed the air out and replace the water. It was just a pity that she didn’t know how to accomplish this.

Sighing, Tilly decided she could do no more. Much as she hated to appear useless, she would have to get help. Luke would be taking Jane out to the plane about now, and Sophie – who would certainly fix it in a flash, she thought wryly – had left, which meant asking Matt. And the matter was urgent. It wouldn’t do for the camp to run out of water.