That’s not great news. At this depth, using unfamiliar equipment, we could easily find twenty minutes of air turning into ten, or five, or none, with no warning. We should be heading for the airlock right now, but I have a lot more work to do if I’m going to test my theory, plus there’s this giant octopus staring me down.

At last, the ship’s exterior lock irises open. Ester jets into the void with the keytar, like she’s about to take the strangest rock solo in history. She must have put unequal pressure in her boots, because she ends up spinning head over heels.

‘I HATE THIS,’ she announces.

‘Relax your feet,’ Gem advises. ‘Okay … now, left and right boots at the same time, one quick burst.’

She follows Gem’s directions. Slowly, awkwardly, she lurches towards us. Her face looks even more shocked than usual, floating in its purple glass fishbowl.

‘Oh, wow,’ she says. ‘Romeo’s big. He’s really pretty.’

I’m thankful she likes animals, even huge scary ones. We don’t need any more bladder accidents.

Ester floats closer and hands me the keytar. ‘Do you think I can touch him?’ she asks.

‘Well, I mean …’

She puts her hand gently on Romeo’s forehead. His skin quivers and pales, but his muscles seem to relax.

‘Okay.’ I shoulder the keytar. ‘Ester, I need you to watch Romeo’s responses. If I do something wrong, help me change course.’

‘What if things goreallywrong?’ Gem asks.

His tone warns me how on edge he is. He has no weapons (thankfully), but he looks ready to drag me back to the ship or punch the octopus in the eye to give me time to escape.

‘It’ll work,’ I say.

I never realized how much of leadership is learning to sound confident when you’re actually terrified.

In truth, I have no idea whether my plan will work. I don’t know if I’m about to make a breakthrough in octopus–human communication or infuriate a one-ton lovesick cephalopod that could snap me like a twig.

‘Nautilus, I need your help,’ I say in Bundeli. ‘I think you brought us here to meet your … your friend. If that’s the case, help me talk to him.’

As I’m explaining to theNautiluswhat I want to ask Romeo, I realize how many things could go wrong. Just translating from one language to another is hard enough. I’m trying to talk to a Victorian-era AI in a rare Indo-Aryan dialect, hoping she can help me accurately relay a message to a creature from another species. But I have to try. I’m a Dolphin. I believe that communication can solve any problem if the parties have the will and the intelligence to learn to understand each other.

I turn on the keyboard. I test a few notes. As Ester suspected, the instrument works just fine underwater. Over my comm, I can hear the notes resonating throughout the ship. I can also feel the vibrations rippling outwards from the hull, as if theNautilusis acting as one massive amplifier.

I turn the keytar’s colour wheel. Romeo seems to find this fascinating. The lights reflect in his great dark eye like Christmas decorations through a rain-streaked window.

I hold a C chord. The notes synchronize with the ship’s lights, turning the dark water an intense shade of indigo. Romeo’s colouration begins to change, matching the blue. The sound waves are strong enough to rattle the seal of my helmet.

‘Is it working?’ Gem asks.

‘Hold on,’ I tell him. ‘I’m still saying hello.’

I play a verse of Adele, just to see how it goes. TheNautilusputs on her light show. Romeo watches my hands on the keyboard. His skin ripples with different colours, as if he’s trying to absorb a new spectrum of information.

‘I think he likes puzzles,’ Ester decides. ‘Try the Bach, something intricate.’

Organ Sonata Number 4 is about as intricate as I can get without tying my fingers in knots. I turn the colour wheel, setting it to brighter hues that normally wouldn’t be visible this deep, then I start to play. TheNautilusobliges with bursts of red and yellow, more like Romeo’s natural pigmentation. About halfway through the song, theNautilusstarts adding harmonic riffs.

Romeo responds with his own palette of colours. His enormous head pulses. Maybe I’m crazy, but I think theNautilusis using my song to send a message.

I hope that message is notHi, buddy! I brought you lunch!

‘Ana,’ Gem says urgently, ‘we’re almost out of air.’

I end the song. The ship’s lights fade to a gentle purple glow.