“This is so much better than sonar or ECDIS,” I murmur. “How is this possible?”

Nelinha looks pleased, like she’s just baked a batch of cookies everybody loves. “I told you, babe—a different perspective on the laws of science. What we’re seeing is a visual representation of the way marine mammals sense their environment. And yeah, it’s way better than puny land-animal tech.”

“Nice work, da Silva.” Tia Romero squints at the controls around the base of the LOCUS. “You’re sure this isn’t making us light up on the radar screens of every ship within a thousand miles?”

“Pretty sure. Like ninety percent. Eighty-five percent.”

“What if the Aronnax has similar tech?” I ask. “Will dynamic camouflage fool a LOCUS?”

Nelinha’s smile turns to a grimace. “Maybe?”

It’s an unsettling thought. There are no signs of other vessels on the LOCUS readout—submarine or otherwise. But is it possible the Aronnax is out there, as invisible to us as we’re (hopefully) invisible to them?

“If they do show themselves,” Gem says, “we’ll test our other new toy.”

He points out the window. On the forward deck, the Sharks have assembled their favorite discovery from the gold-level boxes: a Leyden cannon the size of a Jet Ski. Its coppery barrel is laced with wires and intricate gear work. Its mounted pedestal swivels 270 degrees. I don’t know what it might do to an enemy ship, especially one like the Aronnax, but Gem and his housemates are raring for target practice. I have already warned them they are not allowed to electrocute whales or fishing boats.

The other high point of our trip: The Varuna’s engines freeze up.

I know that sounds like a bad thing. Getting stranded in the middle of the ocean and starving to death would typically fall into that category. However, the Cephalopods are confident that they can make repairs. In the meantime, Halimah Nasser suggests that somebody use this opportunity to do a visual inspection of the hull’s exterior. I volunteer so fast I make her jump.

I get on my buoyancy control vest and scuba tank. I grab my mask, fins, and a dead squid (for obvious reasons). The water is warm enough that I don’t need a wetsuit. I topple backward into the sea. As soon as my cloud of bubbles dissipates, I spot Socrates swimming toward me, delighted to have a playmate.

He chatters and nudges me cheerfully. I give him the squid, but that doesn’t seem to satisfy him. As I start to inspect the hull, he gooses me to get my attention.

“Rude!” I mumble through my breather.

This makes no impression on him. Dolphins are shameless goosers.

He nudges me again, and I realize he wants to show me something.