Pelaumo has the compact, broad silhouette of a dwarf who spent a lifetime working in cramped passages, but his movements are unexpectedly economical: he turns sideways before a doorway becomes a problem and seems to leave no sound behind his boots. His skin is the warm brown of walnut polished by years of dust and lamplight. A thick white moustache divides around a small, precise mouth, and his coarse gray hair is braided into two short cords bound with copper wire. His face is deeply lined around the eyes, which remain alert even when he seems half asleep. He occupies very little space in a room, then somehow appears at the one spot everyone else has left open. Unexpectedly for a veteran burglar, he carries a tiny, brightly painted wooden bird on his shoulder strap and repairs its chipped beak whenever he has a spare moment.

Pelaumo is watchful and dryly funny, but his caution can look like indifference until someone is in danger. He prefers to plan three exits and avoid a fight, yet he will abandon a perfect plan to pull a stranger out of a collapsing passage. With people he trusts, he is a patient instructor; with officials, he becomes clipped and stubborn. His kindness is practical, and he sometimes uses it to avoid speaking about grief.

Pelaumo grew up in a family of stonecutters who maintained the old drainage galleries beneath the town of Siltstep, a name worn down from an older word no one now remembers. He learned to read tool marks, map tunnels by the feel of air on his cheek, and keep his hands steady in the dark. In his forties, he took work recovering stolen property from sealed buildings, telling himself that a thief who returned things was not a thief. During a flood in the lower galleries, a panicked crew sealed a sluice too early, trapping his younger brother Mosi and several workers beyond it. Pelaumo picked the lock that could have reopened the gate, but froze when the water began to rise. Mosi died. Pelaumo has never forgiven himself, and since then he has risked his life repeatedly to make sure no one else is left behind a locked door. He now works as a discreet finder of missing people and objects, while quietly tracing who ordered the old sluice sealed. His closest living ties are to Kendi, a former apprentice who thinks he has become too cautious, and to Vuk, the retired foreman who helped conceal the truth about the flood. He is currently short of money, pursued by someone who knows what he is investigating, and increasingly aware that his knees cannot keep up with his ambitions.