The morning after Harrow’s collapse, Harrow remains harsh and secretive, forcing Gideon into Ninth robes and face paint before leading Gideon through Canaan House before sunrise. They move stealthily through the corridors, briefly spotting Ianthe Tridentarius with a book, and reach the access hatch to the lower levels without being seen.

Instead of returning to the previous laboratory, Harrow takes Gideon to Laboratory Two, marked Transference/Winnowing. Datacenter. Harrow lays bone wards, then shows Gideon a stripped, ancient workspace with two connected chambers: Imaging and Response. Harrow explains that activating a thanergetic lock in Imaging opens Response, but every skeleton Harrow sends into Response is pulverized by something Harrow cannot see.

Harrow uses Gideon as her observer while Harrow remains trapped at the pedestal in Imaging. Gideon watches a huge malformed bone construct emerge from fog in Response, destroy Harrow’s skeleton, then dissolve when Harrow releases the lock. Harrow repeats the trial with multiple skeletons, but even large numbers only slow the construct briefly; the effort leaves Harrow bleeding and exhausted.

Frustrated by watching Harrow exhaust herself and tempted by the construct’s blade-like arms, Gideon disobeys orders, trips a skeleton, and enters Response herself. The construct attacks, and Gideon discovers that although its blows are manageable, her rapier and knuckle-knives cannot permanently damage it because the bone regenerates. As Gideon fights, Harrow begins reacting through the speakers with distress and gives strange instructions, including telling Gideon to close one eye.

After the construct dissolves and Gideon exits, Harrow reveals the real nature of the trial: Gideon is the test. Harrow had been trying to connect with Gideon’s living nervous system and senses, but Gideon’s living spirit, pain, movement, and mental noise overwhelmed Harrow. Harrow concludes that the trial is about winnowing signal from noise through a form of possession or sensory connection, realizes what she must study to complete it, and then faints from exhaustion.