Mara Ironfoot had the depot’s layout drawn on the oilskin before Brekk finished asking his second question.

She drew it from memory, because she had walked the ground itself two seasons ago, before the Threians occupied it. The shelf the depot sat on was a defensible rise with a near sheer drop on its eastern face, which was why the Threians had chosen it.

What the Threians had inherited along with the defensible rise was the stream sixty feet below it. It was the only water source within half a day’s travel of the position.

"They did not dig a well," she said. "The shelf is solid rock under a thin soil layer. A well was never an option for them."

Brekk looked at the drawing. "So they haul."

"They built a winch. A counterweight frame over the eastern drop, cable down to the stream, containers up on the cable."

She tapped the drawing. "I watched it work twice from the ridge above. Two operators, four containers per cycle, six cycles a day for a garrison that size."

"How many people on the slope during a cycle?"

"Two at the winch frame above. One or two at the stream below, filling containers."

Mara traced a line along the slope’s western face with her finger. "The slope itself is the security measure. They post almost nothing on the downslope side, because the terrain does the work for them."

Brekk wrote this down. "And the rotation."

"Six days, confirmed. Next rotation is two days out from today. The one after that is eight days from now."

She looked at him. "A rotation transition is not the best window. New arrivals are alert."

"The middle of a cycle, four days into a rotation, is when a garrison is most settled into routine and least watchful. That is when I would want to be there, if it were my choice."

He understood what she was building toward before she said it directly, which was the kind of understanding Kael had been counting on when he sent her north.

"The winch," he said. "Not the water."

"The water cannot be poisoned without alerting them immediately, and it is their only source, which means they would respond to a poisoning attempt with everything they have. The winch is equipment. Equipment fails."

She turned the drawing so the frame’s axle was facing him. "If the axle bearing seizes under load, it looks like wear, and wear is not something anyone investigates."

"Forward depots do not carry spare bearings for field-built winches. They carry rope, nails, and patience."

"How long to seize a bearing without being seen doing it?"

"One night, if the approach is right. The blind spot on the downslope side rotates with the moon’s position relative to the frame’s shadow. I need three more nights of watching that shadow before I can give you the exact window."

She set the drawing down. "I am not guessing at this. I am measuring it, and I will have the measurement before the rotation changes."

Brekk sat with that for a moment. The assessment Kael had asked for was not a recommendation to act immediately.

It was the shape of what acting would require, so that when the moment came, the decision could be made in minutes rather than days.

"Write it for Kael exactly as you have told me," he said. "Three nights of shadow observation, then a window."

"Target the bearing, not the cable. Timing inside a rotation cycle, not at its edges. He needs the shape of the decision, not a recommendation, because the shape is what he asked for."

She wrote while he watched.

He added one line at the bottom in his own hand: this is an assessment, not a proposal. I am sending it because Kael asked for it, and because the depot’s water posture is the first weakness in this column’s operation that does not require us to match their numbers.

He sent it south with the morning courier.

Before the courier left, Fen came down from the eastern ridge with a small piece of news. It did not change the assessment, but it confirmed something underneath it.

The three Threian scouts who had repositioned to watch the south access trail four days ago had withdrawn back to their original northern ridge position the previous evening.

"They saw the supply convoy," Brekk said. It was not a question.

"They saw a supply convoy go in, and our six go out with empty containers on the return leg, same as always."

Fen shrugged. "Nothing about it held their attention longer than a normal resupply would."

Brekk allowed himself a small measure of satisfaction at that. It was the kind that came from a plan working exactly as designed and therefore producing nothing visible at all.

Mara Ironfoot and twelve additional warriors were inside the Ravine position. As far as the forward depot’s intelligence picture was concerned, nothing had changed.

He found Torr at the supply cache, taking inventory of what the twelve warriors had brought north.

"Three nights," he said. "Starting tonight, you alternate with Mara on the ridge. Same position, same angle on the frame’s shadow, so what either of you records can be compared against the other."

Torr looked up from the inventory. "And if the shadow does not behave the way she expects?"

"Then we learn that too, and the assessment changes before it goes south rather than after."

Brekk picked up one of the supply crates and turned it over, checking the seal. "Kael did not ask for a guess. He asked for a window, and a window that turns out to be wrong is worse than no window at all."

Torr nodded and went back to the inventory.

Outside, the light was beginning to lengthen toward evening. Somewhere north, the depot’s winch would be running its last cycle of the day, four containers up the cable, the same as every day before it, the same as every day until it was not.