Navani conducts controlled experiments using tuning forks to draw Stormlight from one diamond into another, confirming Light responds to specific tones. She escalates to a shielded setup, crossing streams of Stormlight and Voidlight without mixing. Research into ancient music reveals a three-note scale: the first note draws Stormlight, the third draws Voidlight. Raboniel can sing these tones, but Navani uses forks to replicate the effect.

Attempts to infuse a partially drained Voidlight diamond with Stormlight fail; the Voidlight extinguishes the fork’s vibration and the Lights refuse to mingle, behaving “like oil and water.” Consulting the Sibling, Navani learns Towerlight once powered all of Urithiru, and that the Sibling lost strength after losing the ability to hear two pure tones—Honor and Cultivation—insisting Odium’s tone is an interloper.

Raboniel sends a green-tinged gemstone, which Navani identifies as holding Lifelight. Navani successfully draws Lifelight with the tuning fork but still cannot mix it with Stormlight or Voidlight, alone or together, and exhausts the supply. Earlier efforts to move existing Towerlight from its gemstone also failed. Frustrated but undeterred, she plans to disguise weaponized fabrials as abandoned experiments stored in the hallway to prepare a sudden defense.

Returning to the Sibling, Navani asks about the mysterious explosive sphere from invasion day—unknown to the Sibling—and whether an emulsifier could bind Lights. The Sibling insists Lights “come together, as one,” rather than mix, and reports limited awareness: the Windrunner is visible, the Edgedancer seems shrouded by ralkalest, and a female Regal who speaks all languages is intermittently observable. Navani speculates Raboniel seeks hybrid Light to bypass the tower’s protections.

Seeking broader options, Navani suggests the Sibling consider bonding a singer aligned against Odium, citing a Parshendi in Bridge Four. The Sibling hesitates but does not dismiss it, noting any bond would require contact with the pillar and would not restore powers without Towerlight. Navani then negotiates for a node location to protect or cleanse, proposing decoys, sealing with wet crem, and infusing with Stormlight via the aquifers.

Persuaded, the Sibling reveals a node hidden in the well at the Breakaway market on the first floor, reachable through back ways. Moments later, alarmed flashes announce the enemy has already found the node. With time gone, Navani orders the Sibling to contact Kaladin immediately while she prepares to distract Raboniel.