'Virtual net locater, fitted between the cortical stack and neural interface.' The clinical details seemed to give her strength. Her voice firmed up. 'We did the surgery two days before you were freighted. Microscalpelled into the vertebrae along the line of the original stack incision, and plugged it with graft tissue. No show under any kind of sweep outside virtual. You'd have to run a full neuro-electrical to find it. How did you guess?'