The stone door had no seams.
It was not opened by pushing from outside.
Dozens of white chakra tubes converged at its center. Only when the tubes contracted in a specific sequence would the entire slab of rock sink into the ground.
The living White Zetsu refused to provide the sequence.
The Sealing Squad did not forcibly sever all the tubes, either.
If the stone door was connected to a life-support structure, destroying it recklessly could wipe out the traces left behind it.
The Cross-Verification Squad first numbered each tube, then observed the natural flow of chakra.
Seven had long since stopped functioning.
Nine were still slowly drawing in underground energy.
The remaining tubes reacted only when White Zetsu approached.
The Hyuga jonin touched each one with a tiny amount of chakra, recording the changes inside the stone door.
After tubes three, eleven, and seventeen contracted in sequence, a hollow slot large enough to hold a White Zetsu core appeared at the center of the door.
The real key was not a coded formula.
It was a White Zetsu.
Konoha had not brought the living White Zetsu to the site.
The Medical Squad used shed tissue and a simulated core to make a single-use Chakra Key.
The key could last only three breaths, preventing whoever controlled the area beyond the door from establishing a connection back through it.
As the stone door slowly sank, the air in the Mine Tunnel changed.
There was no smell of decay inside.
Only the mingled scents of dry medicinal compounds, old wood, and lime.
The hidden space was larger than expected.
A stone bed stood in the center.
Several white tubes stood beside it. Some had withered, while others were still connected to the underground root system.
Medicine bottles, a broken scythe, and numerous