Taking her own advice to heart, she persevered on the ladder, her feet slipping on the slick metal as a cold layer of slime coated her hands. With her torch in her pocket for safekeeping, she descended into complete darkness, tapping each rung with her boot before she trusted her weight to it, and eventually stepping off onto a narrow concrete ledge. She took out her torch and panned it around a vast expanse of turbulent water enclosed by lichen-covered walls. She couldn’t see Rosie anywhere.

“Rosie?” The rank air made her cough until she doubled over. She took her inhaler and tried again. “Rosie!”

Gauging the direction of the current, she set off along the ledge, keeping one hand in contact with the wall for balance and using her other to aim the torch.

“Rosie!”

At regular intervals, she paused to shout and listen for a response, though it was difficult to isolate anything beside the constant white noise of the flood. She heard sporadic thumps as rubble ricocheted off the walls, the slosh and slide of her own laborious progress, and then finally, faint and wavering and not too far ahead, the incongruous sound of singing.

“Keep going, Rosie,” she whispered. “Pick another verse. I’m almost there.”

She couldn’t run—she could barely increase her pace beyond the tentative steps she was taking—but she could see Rosie’s hair now, and make out a tuneless but determined refrain from “Amarillo.” The lyrics stopped as Rosie spotted the light, and her hand appeared above the ledge, waving frantically.

“Down here,” she yelled, her voice hoarse and broken. “Here. I’m down here.”

Jem shoved her kit against the wall, and then knelt and clasped Rosie’s hand in both of hers. “Hey, I’ve got you. I’ve got you.”

“Jem?” Rosie’s head shot up, but she was blinking, blinded by the glare of the torch after so long in the dark. Her bottom lip quivered. “Are you really here, or did I die?”

Jem stroked Rosie’s forehead, avoiding a jagged laceration. “You haven’t died, you silly sod, but you’ve got yourself in a bit of a pickle.”

“I didn’t mean to.” Rosie’s face crumpled, and she started to cry. “I can’t get out. I tried, but there’s metal in my leg and I can’t pull it, it’s proper stuck, and the water’s coming up. You should go, Jem. I don’t want you to watch. Please don’t watch.”