The generator had been idle all afternoon, according to the summary.
According to its meter, it had gained another hour.
Yanchuan placed the two records beside a client calculation on his office screen. Then he closed the records. Chen was coming down the aisle, and the calculation was already late.
“Are you going to hide it every time I walk past?” Chen asked.
“I’m doing the work.”
“You’re doing two things badly. Finish ours, then take the room at six.”
Yanchuan wanted to object to the word ours. He knew what Chen meant. Two colleagues had covered his absence. One had postponed a visit to her parents. He finished the calculation, checked it, and sent the assumptions with the chart.
At six, he called Han Rui from the empty meeting room. December rain streaked the window. The generator entry had survived three rounds of clarification because the maintenance export used cumulative engine hours, while the report described a calendar period. Nobody had supplied both adjoining readings until that morning.
Han asked him to read them aloud.
“An hour,” Yanchuan said.
“At that resolution. You haven’t found an exact start time.”
They checked the meter identity and the interval between readings. An engine could run unloaded for a maintenance check. A reading could be entered late. A rounded display could cross a boundary during a shorter run. Any of those might explain the difference without a secret operation.
Yanchuan wrote the possibilities down. He resented each one as it appeared.
“Now ask what connected to it,” Han said.
The authorized circuit list named the primary cold-storage loads and a service feeder. The witnessed demonstration had concerned a different supply arrangement. Yanchuan had almost treated every circuit at the site as part of the same test because he had traveled there for one question.
Amina answered the next morning during her break. She had asked the maintenance team about an unloaded run. Their retained work ticket described a loaded check of the service feeder. The date fell inside the period the contractor’s summary called unavailable for operation.
“Can they give the start time?” he asked.
“Not from this ticket. And I am not asking somebody to invent one for us.”
She sent a revised technical response through the operator. It included the uncertainty, the feeder identifier, and the distinction between unavailable to the acceptance test and physically inactive. The contractor had used the two descriptions interchangeably in an earlier reply.
The answer came three days later. The test summary excluded separately maintained service facilities. A loaded maintenance run did not, in the sender’s view, contradict the acceptance package.
Yanchuan read the sentence from the lift to his desk. It supplied a boundary nobody had mentioned when they first requested records of the assignment.
He called An at lunch. She was taking a bus between clients and asked him to wait until she could hear.
“There’s another part of the site,” he said when she called back.
“Another building?”
“I don’t know yet. A service feeder outside the package.”
“Outside the package isn’t outside the case.”
He opened the transport invoice. Return to service office. The words had been there for weeks, attached in his mind to a room with desks. A service facility could contain workshops, stores, offices, any number of ordinary places. He had no reason yet to choose one.
Wanjiru asked for a concise explanation of why the scope mattered. He wrote two pages. She returned them with a request for half a page and the supporting references attached separately. The investigators did not need his entire education in cooling systems to ask who maintained a feeder.
By ten that night, he had finished. He left the company name and the technical identifiers in place. He removed a paragraph beginning, This is where he must have gone.
His father called before he shut down. Jianming was repairing a neighbour’s lamp and had stopped because the replacement fitting was wrong.
“Close enough?” Yanchuan asked, remembering a childhood argument.
“For a lamp that doesn’t need to work.”
Yanchuan smiled for the first time that day. After the call, he sent the half-page explanation and put the generator record away. A machine had run when a report seemed to say nothing had. He had found a question about the report’s boundary, not an hour he could place inside his brother’s life.