Catrin has a long, angular face made more expressive by a sharply lifted brow and a mouth that seems ready to correct someone. She smells unmistakably of damp paper, lampblack, and the bitter fennel lozenges she chews to stay alert, and she knows it; she keeps a tin of lozenges open on her desk for anyone who complains. She waits with her weight on the balls of her feet, as if the ground might offer a new fact at any moment. Her movements are economical and quick, except when she traces a route in the air with one ink-marked finger.

Catrin is methodical enough to label the uncertainty in a report and sharp-tongued enough to make its author regret hiding it. She is courageous when a discovery or a crew member is at stake, but her courage is not fearlessness: anxiety makes her more controlling and more exact. In calm company she can be wry and unexpectedly generous with her time; under pressure she becomes brisk, argumentative, and fiercely attentive to who has been left behind.

Catrin joined the Far Landing Survey as a junior copyist, believing accurate maps could keep people alive as well as make the expedition famous. During her first season, a guide named Oru warned that a marked ravine had shifted after a flood. The expedition leader dismissed the warning, and a supply team was trapped when the route collapsed. Catrin helped organize a night rescue by comparing field notes and old water lines, but one teamster, Jori, died before help arrived. Since then, she has insisted that uncertain terrain be marked as uncertain, not cleaned up for a sponsor's comfort. She became senior recorder by patiently reconciling years of contradictory sketches, and now presses to publish the maps before wealthy investors can claim them as private property. Her chief opponent is expedition patron Vey, who argues that premature publication will endanger future crews. Her closest ally is the practical quartermaster Tavi, with whom she argues over every spare coil of cord. Catrin is also trying to keep the present crew together through bad weather, dwindling supplies, and the knowledge that another survey team may already be approaching the same dangerous country.