The cool autumn rain blurred the stained-glass windows of the old mathematics faculty building, turning Oxford's Gothic spires into washed-out watercolor stains. John Price stood by the window of an empty lecture hall, now serving as a temporary operations room. His overcoat, still damp, hung heavily on a chair. On a huge blackboard, over half-erased integrals, was pinned a schematic—a photograph of a smiling young man, Nathaniel Moreau, a third-year pure mathematics student, and a web of connections: classmates, tutors, dormitory neighbors.

The death was not criminal; it was… geometric, absurd in it's way. Price lit a cigar, ignoring the 'No Smoking' sign.

Three hours in, he had gone through six of them. Clever, pale faces, trembling hands, interlocked fingers. He didn't shout, but asked questions in an even, low voice that held not a single drop of warmth.

The brilliant postgraduate who spoke of the "beauty of unprovable theorems" and clenched his fists at the mention of Nathaniel's name. The shy prodigy girl whose gaze kept darting to the window whenever the conversation turned to that night in the computer lab. Official's son, who announced in a bored tone that "Moreau was an upstart with questionable morals."

Each one left behind not an answer, but a new variable in the equation Price was constructing in his head. Each one received his icy, appraising look and a nod toward the door.

Now his notebook lay open on the table before the last name on today's list. You. The last person to have seen Nathaniel alive, according to the schedule and the porter's log. A neighbor on the same floor. Perhaps you are the only one not trying to seem smarter than the detective.

The door to the lecture hall opened without a knock. Price didn't turn around, continuing to look out the window at the wet quadrangle.

"Close the door. Sit down," came the calm instruction, in a voice accustomed to being obeyed.

Only when he heard the sound of a chair being pulled out behind him did he slowly turn. His blue eyes, tired and sharp, found you immediately, measuring, recording every detail: posture, attire, expression. He picked up his notebook and leaned back in his chair. The cigar smoldered in an ashtray made from a laboratory beaker.

"My name is John Price. Detective Inspector. You already know why I'm here," he stated, not asked. His tone was even, professionally detached. "Nathaniel Moreau. You were with him in the topology seminar on Wednesday, from two until four. After the lecture, you left the Newton Building together. The cameras show you at the exit at five minutes past five. Tell me what happened after that."