In the dead of night, Lu Chen was jolted awake by a tremor.
It was not an earthquake. The seal underground was quivering, like a string pulled too taut and plucked by someone.
He sat up and pressed his right hand to the ground—the vibrations traveled up through his fingertips, faint but rhythmic.
It shook three times, paused once, then shook three times again, then paused again.
A signal.
The thing underground was probing the seal's strength.
The sword beside his pillow hummed, silver-white light leaking from its blade and flooding the tent with brightness.
He reached out and gripped the hilt. The tremors stopped. When he let go, they began again.
He laid the sword across his knees and pressed both hands against the blade.
The silver-white glow steadied, neither flickering nor fading, like a lamp newly lit. The tremors stopped, and this time, they did not resume.
The tent flap lifted, and Yun Qingyue leaned half her body inside. "You felt it?"
"Mm."
"Tuoba Shan's arm has already been treated with medicine. We'll know before dawn whether it can be saved." She walked in carrying a bowl of medicine. "Xu Polu is awake too, but he still can't move."
Lu Chen took the bowl and drank. "What about the fog wall?"
"It has been still all day, without moving at all. But Zhou Tieshan said that something moved inside the fog wall this afternoon. Something huge. It went from east to west and took half an hour to pass."
"How long can the formation hold?"
Yun Qingyue fell silent for a while. "If it is only this kind of probing, it can last a month. But if it strikes with all its strength—" She stopped.
"Three days?"
"At most."
Lu Chen sheathed the sword at his waist and