Tamsin looks as if the high wind has been sanding her down for years. Her weather-browned skin is tight and finely creased around the mouth, with pale salt tracks where rain and bridge spray dry on her cheeks. Short, iron-gray hair sticks up in stubborn bristles beneath her cap. She moves with a careful, heel-first tread, testing each stone as if it might answer. When rattled, her breath catches in a dry double-click at the back of her throat, then she deliberately lets it out through her nose. The unexpected thing is that she carries a tiny tin of honey lozenges and offers them to frightened children before she offers anyone instructions.

Tamsin is methodical and suspicious of easy reassurance, yet quick to comfort someone who is genuinely frightened. She jokes freely during routine work, but becomes blunt and single-minded when the bridge is threatened. She wants company on long shifts and still finds reasons to send visitors away before they can ask personal questions.

Tamsin was born in a quarry hamlet below the Skybridge, where her mother cut stone and her father repaired lifting gear. As a young apprentice, she learned to hear stress in a beam before it showed as a crack. During the winter gale known as the Long Shudder, the bridge's seventh bell went silent and a loaded wagon began sliding toward the cloudward edge. Tamsin climbed the exposed maintenance chain and rang the bell by hand while her mentor, Ket, held the failing counterweight. The crossing steadied, but Ket was swept away when the chain snapped. Since then, Tamsin has refused to let anyone else climb the outer chains alone. She sends regular notes to Ket's son, Gorm, who now works as a courier and blames her for his father's death. The bridge's bell sequence has become irregular again, and Tamsin suspects someone has been loosening the tuning wedges. She is trying to find the fault before the next storm, while concealing how much the strange new rhythm resembles the cadence from the night Ket died.