"It’s been three days," said Zebulun. "How long can you keep this up?"

Sarah looked up at him with weary eyes. "It gets more exhausting each day. I’ve already drawn too much energy from the environment. Were I to keep this up longer than five days, the forest itself would be harmed."

"After that?" asked Zebulun.

"I would need to wait a few weeks before doing it again," said Sarah. "The forest needs time to return to equilibrium."

"So," said Davion, staring out of the cave mouth, "In three days, we’re in trouble."

"Yes," said Sarah. "Unless the serpent makes a mistake."