Navani reread the passages, then inspected the pale green light she had split out of the Towerlight. Lifelight, the Light of Cultivation. Could Gavilar have had this Light too? Could she have mistaken Lifelight diamonds for emeralds? Or, would Lifelight in a gemstone appear identical to a Stormlight one at a casual glance?

“Why wouldn’t you talk to me, Gavilar?” she whispered. “Why wasn’t I worth trusting.…” She braced herself, then read further in her account—right up to the point where Gavilar plunged the knife in the deepest.

You aren’t worthy. That’s why, she read. You claim to be a scholar, but where are your discoveries? You study light, but you are its opposite. A thing that destroys light. You spend your time wallowing in the muck of the kitchens and obsessing about whether or not some lighteyes recognizes the correct lines on a map.

Storms. That was so painful.

She forced herself to linger on his words. You are its opposite. A thing that destroys light …

Gavilar had spoken of the same concept as Raboniel, of light and its opposite. Coincidence? Did it have to do with that sphere that bent the air?

The guard at her door began humming, then stepped to the side. Navani could guess what that meant. Indeed, Raboniel soon entered, followed by that other Fused who was so often nearby. The femalen with a similar topknot and skin pattern, but a blank stare. Raboniel seemed to like to keep her near, though Navani wasn’t certain if it was for protection or for some other reason. The second Fused was one of the more … unhinged that Navani had seen. Perhaps the more sane ones purposely kept an eye on specific insane ones, to prevent them from hurting themselves or others.

The insane Fused walked over to the wall and stared at it. Raboniel walked toward the desk, so Navani rose and bowed to her. “Ancient One. Is something wrong?”

“Merely checking on your progress,” Raboniel said. Navani made room so Raboniel could bend down, the orange-red hair of her topknot brushing the table as she inspected Navani’s experiment: a box letting out the illumination from a Towerlight gemstone, which was split through a prism, then recombined through another into two separate streams of light.

“Incredible,” Raboniel said. “This is what you do when you experiment, instead of fighting against me? Look, Stormlight and Lifelight. As I said.”

“Yes, Ancient One,” Navani said. “I’ve been reading about light. The illumination that comes from the sun or candles cannot be stored in gemstones, but Stormlight can. So what is Stormlight? It is not simply illumination, as it gives off illumination.

“It’s as if Stormlight is at times a liquid. It behaves like one when you draw it from a full gemstone into an empty one, mimicking osmosis. While captured, the illumination given off by Stormlight behaves like sunlight: it can be split by a prism, and diffuses the farther it gets from its source. But the Stormlight must be different from the illumination it radiates. Otherwise, how could we hold it in a gemstone?”

“Can you combine them?” Raboniel asked. “Stormlight and Voidlight, can they be mixed?”

“To prove that humans and singers can be unified,” Navani said.

“Yes, of course. For that reason.”

She’s lying, Navani thought. She couldn’t be certain, as singers often acted in strange ways, but Navani suspected more here.

The strange insane Fused began saying something in their language. She stared up at the wall, then said it louder.

Raboniel glanced at her, hummed softly, then looked at Navani. “Have you discovered anything more?”

“That’s about it,” Navani said. “I couldn’t get Lifelight and Stormlight to recombine, but I don’t know if this counts as truly splitting them apart—as I’ve only split their radiation, not the pooled Light itself.”

“I’ve thought about your mixing of oil and water, and I am intrigued. We need to know. Can Stormlight and Voidlight be mixed? What would happen if they were combined?”

“You are quite focused on that idea, Ancient One,” Navani said, thoughtfully leaning back. “Why?”

“It’s why I came here,” Raboniel said.

“Not to conquer? You talk of peace between us. What would that alliance be like, to you, if we could achieve it?”

Raboniel hummed a rhythm and opened Navani’s box, taking out the sphere of Towerlight. “The war has stretched so long, I’ve seen this kind of tactic play out dozens of times. We have never held the tower before, true, but we’ve seized Oathgates, taken command posts, and held the capital of Alethela a couple of times. All part of an eternal, endless slog of a war. I want to end it. I need to find the tools to truly end it, for all of our … sanity.”

“End how?” Navani pressed. “If we work together like you want, what happens to my people?”

Raboniel turned the Towerlight sphere over in her fingers, ignoring the question. “We’ve known about this new Light ever since the tower was created—but I am the one who theorized it was Stormlight and Lifelight combined. You have confirmed this. This is proof. Proof that what I want to do is possible.”

“Have you ever heard of spheres that warp the air around them?” Navani asked. “Like they were extremely hot?”

Raboniel’s rhythm cut off. She turned toward Navani. “Where did you hear of such a thing?”

“I remembered a conversation about it,” Navani lied, “from long ago—with someone who claimed to have seen one.”

“There are theories,” Raboniel said. “Matter has its opposite: negative axi that destroy positive axi when combined. This is known, and confirmed by the Shards Odium and Honor. So some have thought … is there a negative to light? An anti-light? I had discarded this idea. After all, I assumed that if there was an opposite to Stormlight, it would be Voidlight.”

“Except,” Navani said, “we have no reason to believe that Stormlight and Voidlight are opposites. Tell me, what would happen if this theoretical negative light were to combine with its positive?”

“Destruction,” Raboniel said. “Instantaneous annihilation.”

Navani felt cold. She’d told her scholars—the ones to whom she’d entrusted Szeth’s strange sphere—to experiment with the air-warping light. To move it to different gemstones, to try using it in fabrials. Could it be that … they’d somehow mixed that sphere’s contents with ordinary Voidlight?

“Continue your experiments,” Raboniel said, putting down the sphere. “Anything you need for your science shall be yours. If you can combine Voidlight and Stormlight without destroying them—therefore proving they are not opposites … well, I should like to know this. It will require me to discard years upon years of theories.”

“I have no idea where to begin,” Navani protested. “If you let me have my team back…”

“Write them instructions and put them to work,” Raboniel said. “You have them still.”

“Fine,” Navani said, “but I have no idea what I’m doing. If I were trying to do this with liquids, I’d use an emulsifier—but what kind of emulsifier does one use on light? It defies reason.”

“Try anyway,” Raboniel said. “Do this, and I’ll free your tower. I’ll take my troops and walk away. This knowledge is worth more than any one location, no matter how strategic.”