Brother Aldous Pyre is thin and stooped, with the forward lean of someone who has spent years reading small script by poor lamplight. His grey robes hang a little too long and are patched at the elbows with darker squares of cloth. Ink has worked into the seams and the creases of his fingers. A small pouch of coins jingles at his belt whenever he moves, though he walks with a careful, nearly soundless shuffle. His spectacles hang from a fine chain and catch the light when he turns his head. Unexpectedly, the plain wooden staff he carries is polished to a soft shine, with tiny, meticulous carvings of moths along its grip.

Aldous is meticulous but not cold: he will spend an hour checking a widow's claim, then forget to eat while doing it. With frightened people he is patient and plainspoken; with officials who dismiss them, he turns exacting and dryly confrontational. He wants the truth public, yet fears what careless disclosure can do, so his care for others often looks like frustrating delay.

Aldous was raised above his mother's cramped bookbinding shop, where he learned that a clean copy could preserve a life as surely as a surgeon's stitch. As a boy, he was apprenticed to a municipal record office and later entered the service of a Knowledge Domain chapel, the House of the Open Index. His turning point came during a winter flood, when officials ordered him to destroy a register that proved an entire riverside ward had paid its taxes. He hid the pages in a flour barrel and spent the night ferrying them to higher ground. The ward survived the next season's eviction, but the chapel censured him for breaking the chain of custody. Now he keeps the chapel's ledgers and quietly compares them with surviving copies of the old tax rolls. His closest ally is his former teacher, Sister Oda, who believes the truth should be revealed carefully; his younger brother, Tomas, wants him to publish everything at once. Aldous is trying to find the missing original register before the city's new assessor does.