They watched in silence as Oscar walked the final few steps, then Lara, limping slightly, and there were audible sighs of relief as the two of them jumped down off the tree. But there were still five of them on this side—Barney, Jess, George and Alice with the boat, and Tom.

Joel studied the ground, talking to Shen, who shook his head and looked more than once across at Barney, as if hoping for guidance. Joel kicked at the earth on the lip of the ravine, and when more debris tumbled away, he pushed at the trunk of the tree as if trying to prove how solid it was.

Tom heard Barney say, “Jess?”

He turned and saw that she’d climbed up onto the tree.

She smiled at Barney, then at Tom, a smile he understood and mistrusted all at once, and she said, “What Joel’s doing won’t tell us anything. I’m the lightest.”

And with that she walked down the fallen trunk, hardly holding on to the guide rope at all. Halfway across she stopped and turned to look back at them, and Tom felt an instant sinking fear in his gut, that she was about to throw herself into the void. But then she shrugged, as though she’d only been trying to show them how easy it was, and continued on her way. More earth fell away as she neared the end, though the tree didn’t move.

Joel didn’t even notice her approach until the last few seconds and jumped back in shock, but then, as if it had been his idea, he shouted, “Great, we can do this. Barney, you’re up next.”

Barney crossed, and this time there was no further collapse. Tom helped George and Alice lift the boat up onto the trunk, then climbed up behind them and stood where the rope was tied to the upturned root.

He said, “As soon as you’re across with the boat I’ll untie the rope and follow.”

The two of them set off, forced into the same baby steps the others had used carrying the boat case, trying to halt their downward momentum along the sloping trunk. The others followed every movement. The far side looked stable now, and yet still he sensed something was wrong.

He could feel some sort of movement in the trunk beneath his feet, and at first he thought it might be the vibration of George and Alice’s steps, but it was more of a straining, like a rope creaking as it stretches to breaking point.