IT’S LATE WHEN WE GO BELOW. CHARIS IS AT THE wheel and Marcus will be on watch with her when he goes back up. The sky is white with stars and it is uber-awe-inspiring. I’d stay awake all night if my eyelids didn’t feel like lead. The jet lag has really hit me now. Jen and I need to at least try to get a few hours’ sleep, because we’re going to have to make sure the night watch have something to eat later, but before we bunk down for the night, Jen hooks her iPad up to the satellite broadband and shows us today’s news on iPlayer. The BBC has edited our segment so much you wouldn’t even know I was there. Mum is going to be gutted.

Jen shows us all the Spirit of Freedom blog entry next, which also has no reference whatsoever to yours truly. Everyone else is featured, Ash looks especially godlike (I’m surprised she hasn’t plastered a soft-focus filter all over him), and there’s a link to a YouTube video she’s uploaded of our dolphin encounter.

“So … what do you think?”

She’s asking me? I can’t believe it. She hasn’t spoken to me all day. I’m lost for words.

“It’s …”

“… missing something?” Ash finishes for me pointedly.

“Damn right.” Marcus. “For one thing, you’ve only gone and captured my bad side in every shot, like, and for another — where’s Rio? She’s part of the team, too.” He gets his phone out and fiddles with it. “Squeeze in, pet, and I’ll get you on here.”

Jen elbows him. “I haven’t had a chance, okay? None of you have even noticed that I’m hardly on it, either. In case you’ve forgotten, we’re the support team. You lot are the main attraction.”

“I’ll get you next, then. Out here we’re a team.”

“No, you won’t. Get out of the way, Marky. I’ll do it.”

Ever the joker, Marcus obstructs Jen every time she tries to get around him, so she has to try to take a picture over his shoulder. While he’s fighting her off he says, “Put your heads together, man, I can’t get you all in.”

“Marcus!” Jen is laughing despite her annoyance. “Ash! Tell him!”

I can feel Ash’s cheek against mine, rough and hot from a day in the sun. He pulls away slightly and shifts in his seat.

“Look over here, Rio, not at the floor, for God’s sake! Work it, baby, work the camera — rrrrrrr …” Marcus jokes.

I look up and the flash goes off.

Marcus leans back and pinches at his screen, zooming in and out. “Beautiful, like. Very photogenic, Rio. Nice. You want me to send it to your iPad, Jen? You could upload …”

She’s already on her way to her bunk.

Marcus looks at us. “What’s eating her, man? Was it something I said?”

Ash gets up. “Leave it, Marky. Give her some space. Shouldn’t you be on deck anyway?”

Marcus raises his hands and shrugs at me. “She needs space? On here?” He makes a face at me as he makes his way to the steps. “Welcome on board, Rio. Hope you’re thick-skinned as well as beautiful.”

My cheeks flush red-hot and I wonder if Marcus needs his eyes tested. Thankfully he doesn’t notice. While Ash goes to sit down by the radio I try to work up the courage to face Jen by imagining her lying on her bed in oversized SpongeBob pj’s, wearing a green face mask with two thick cucumber slices on her eyes.

Ash checks our position and calls our coordinates in to the Cape Town support team. “Hey, Chris. Yeah.” He looks at me briefly. “We’ve made really good time today. Say again? No, just bad static. I’m changing to channel twenty-eight.” He twists a knob, looks at his hand strangely, rubbing his fingertips together, before wiping them on the leg of his shorts, leaving an oily smear. “You there? That’s a bit better.” Ash leans forward and whispers to me while Chris is speaking to him, “Rio, can you get me a cloth?”

I find an old rag in the kitchen and leave him rubbing the radio clean. Then I pour a drink and reluctantly make my way forward, only to find that Jen is still in the “head.” Sheesh! How long does she need? I jump up onto my bunk to wait.

When she finally emerges, the room fills with an overpowering cloud of perfume. I recognize it: JLo Glow. Who wears perfume to bed? She looks softer now that she’s peeled away that layer of makeup she hides behind — it seems that getting it off properly is as important to her as putting it on.

“Look, we got off to a bad start …” I begin.

“No. You got off to a bad start.” Jen reaches into a drawer and pulls out a sleep mask. She pulls it onto her forehead and I have to try not to laugh. How is this girl going to cope when things get rough?

“But can’t we at least try to get past that?” I continue. “We’ve got to spend the next seven months cooped up in here.”

She sighs. “Maybe. It depends.”

“On what? What does it depend on? I’ll be your slave …” I joke.

Amazingly, my stupid attempt at humor makes her laugh. “You will?”

“Command me.”

“Don’t be an idiot.”

Back to form then, but at least I’ve confused her by being friendly.

“Rio,” she says, “I really want this thing to succeed, for Ash. I don’t want anything else to go wrong.”

“Neither do I!”

Jen snorts. “Okay, then. Prove it to me. Then we’ll be best buddies.”

“Really?”

“Yes, really,” she says huffily.

“Thanks.”

She exhales slowly before pulling the sleep mask over her eyes and saying, “You’re welcome. Now are you going to get into bed, or what? Because I need the light off.”

Over the next few days we all fall into a routine and I begin doing what I do regularly whenever I go out back home: people-watching. We’ve been lucky with the weather — mostly sunny — and the seas around South Africa’s southernmost tip, Cape Agulhas, are hilly but nothing we can’t handle. This is the place where the Atlantic meets the Indian Ocean’s strong currents, and it is renowned for its huge waves, but it barely troubles Spirit.

One thing seriously freaks me out when I first hear it — Marcus sometimes cries out in his sleep during the day watch. I can guess why he does it. A couple of times, when it is really bad, Ash goes below to see how he is. Nobody speaks about Afghanistan in front of me and I don’t like to ask, not yet. Charis and Jen whisper a lot — I’m trying not to be paranoid, but I can’t help thinking that a lot of it is about me.

One day, when Jen goes below deck, Charis shows me how her fingers work, how they are triggered by her own arm muscles. In contrast I notice that Ash hardly ever takes his prostheses off, even though they seem to give him grief from time to time.

Izzy is just Izzy. She likes to watch people, too. From time to time even she goes pale and pops painkillers, but her biggest issues are making sure nothing gets snagged in her scaffolding and that she eats at regular times. At first I couldn’t work out how she got her shorts on, but then I noticed that they have been custom-made for her. A zipper running from her waist to the hemline has been sewn into them on the side of her injury — very clever.

When I’m serving lunch to the day shift I sit next to her at the cockpit table and ask, “How long do you have to have that frame attached to your leg? Forever?”

“No. About eight weeks. It’s pinned to the bones to help them heal straight.”

“But I thought your helicopter crash was months ago. How come you need this now?”

“My leg healed with a twist in it and they decided to rebreak it in multiple places two weeks ago. So you can thank me for all this …” With a sweep of her arm Izzy encompasses all we can see — basically, ocean and boat.

I can’t help but laugh at the comical expression on her face. “And how do you figure that?”

“Easy. I’m the reason you’re here, baby. Until they decided to rearrange my tibia I was going to be the other able body.”

“Hang on — doesn’t that mean you’re going to have to have that thing removed in six weeks or so?”

Iz grins. “Nothing, and I mean nothing, was going to stop me from coming on this trip. We’re going to have a brief stopover in Jakarta, where this baby is coming off.”

We’re quiet for a minute or two and then I decide to share one of my observations. “Ash looks like he’s in pain sometimes with his prostheses. Is that normal?”

“Probably. He’s just being macho.” Iz laughs. “Marcus won’t let anyone know what he’s going through, either. That’s what soldiers do — they just get on with it. With or without limbs …”

While I’m people-watching I also start to notice the way Ash is only fine with me if Jen isn’t around. I don’t get it. The thing is, they look like they are an item but they don’t ever seem to do the things couples should do. I mean, they touch — she’ll even sit with her arm around his shoulder sometimes, but it’s all lacking … something. But hey, who am I to judge? Both my ex-boyfriends have been pretty pointless. They went right off me the minute they met Gran or Mum and had to decide between joining the church choir or a barrage of questions and the prospect of an arranged marriage. I’m way too complicated for love. I suppose I could ask Izzy or Marcus to dish the goss, but I know they’ll wonder why I’m asking. Or worse, they’ll assume they know why I’m asking. So I don’t. I’m not interested in him in that way, I just want to know the score.

A couple of times I find Ash sitting in the comms chair with his legs off, recharging them. He’s so at ease with me seeing his disability — or at least he seems to be. Sometimes when he sits there rubbing his stumps I wonder if he’s trying to freak me out. If so, it’s not working. There’s just something about the way he is that I can’t shake out of my head. It makes me want to spend time with him. The only trouble is, anytime I’m around him I turn into a brain-dead idiot and, when I speak, my words just seem to drop from my mouth and flap around my feet like dying fish.

On day five I’m up at dawn to get breakfast sorted for the day watch, but I decide to head up on deck first because I can hear music. It’s quiet, mostly drowned out by the rush of the sea and the wind that has kept us almost constantly under sail since we left Cape Town. But what I can catch sounds amazing. Like Ed Sheeran has dropped in to give us a free “unplugged” session, except it keeps stopping and starting. In fact, I’m pretty sure the song is “Lego House.”

Charis has gone to get her head down — I can hear her arm humming in her cabin and then falling silent. Marcus is making a couple of drinks in the galley before he does the same. He’s wearing a black T-shirt that says Only trust people who like big butts — they cannot lie. I try not to encourage him by snickering.

“Where’s the music coming from?”

He tickles me in the ribs when I try to squeeze past him. “Someone strangling a freaking cat? It’s either that or this thing is haunted. Want a soda?”

“No, thanks.”

I go up to the cockpit. Izzy is at the wheel. She nods her head in the direction of the mast and puts a finger to her lips, so I creep around to have a look. Ash is there, Jen’s iPad on his lap, and he’s leaning against the mast, strumming on the thinnest guitar I have ever seen. It is little more than a neck. Ahead of us is a staggering violet-and-orange sunrise. The ocean is on fire. I’m not kidding, you can’t tell where it ends and the sky begins.

Ash stops playing when he realizes I’m watching.

“Don’t stop.”

“I’m just learning the lyrics.” Embarrassed, he shows me the iPad screen. There’s a video of Ed Sheeran on it, paused. Ash looks like he’s about to put it away.

“So — keep learning.”

With a shrug he starts playing the guitar again, a throbbing, pulsing rhythm interspersed with this incredible bass line. When he starts singing, his voice is breathy and quiet, but somehow it slices through the background noise. He stops suddenly when he gets to the line about surrendering up his heart, as if it troubles him.

“That’s as far as I’ve got,” he tells me, but I know he’s just being modest.

“It’s beautiful.”

“The sunrise?”

“No.” I laugh, tucking some strands of flyaway hair back and sitting next to him. “Your voice. Seriously, you should record that.”

“Not likely. Do you play?”

My hair falls forward again. “Are you kidding? No. I mangled the recorder when I was younger — until Mum hid it. Borrowed a school violin for a while, but we couldn’t afford lessons.”

Even his laugh is musical. I’d never noticed. Come to think of it, I’m pretty sure this is the first time I’ve heard it. He holds out the guitar. “Here, I’ll show you how.”

The word no is on my lips, it really is. But I can’t say it, because this is the most he’s said to me in five days. Ash puts the instrument onto my lap while I’m wedging my crazy hair back behind my ear again, takes my left hand in his, and positions it, moving my fingers onto the strings one by one.

“What do I do with this one?” I ask, holding up my right hand.

He laughs. “Impatient, aren’t we?”

My fingers shake a little when he finally releases them. Don’t think about it. If I think, I blush.

“That’s a chord,” he tells me. “C, with an added second.” When I do nothing with it he reaches over and strums the strings for me. It sounds amazing. It sparkles. I can feel the vibration of the guitar against my chest.

“It doesn’t play itself,” he says, grinning. “Use your thumb or something.” Then he’s moving the fingers of my left hand again. “And this is G.”

I strum this one myself. The vibration is deeper this time.

“You see?”

My mouth is dry. “Easy. Yes. Until I have to move them on my own …” I hand the guitar back and he looks crestfallen. “You going to sing ‘Lego House’ to Jen?”

Suddenly he’s serious again and I wonder why my mouth keeps losing any connection with my brain. “What? Why would I sing it to Jen?”

“I just thought … Never mind.”

He’s squinting at me like the sun is in his eyes, he raises a hand to rub them while I’m wondering, Why do guys always have such insane eyelashes? “Oh, I get it …” He breathes out, long and slow. “Jen and me. It’s complicated. Something I need to deal with and I’m not doing it too well, okay? This happened.” His fingernail clinks against his metal shin as he taps it angrily.

“You don’t need to explain, Ash — really.” Why can’t I keep my big mouth shut? I’m on overload, so I stand up. Don’t know where to put myself. “It’s none of my business,” I say. “Keep playing — please. Nice music, Ash, really. Must go anyway. I’ve forgotten my sunglasses.”

“If you have to … You haven’t upset me, I’m just mad at myself, at the situation.”

I think he’s finding my awkwardness funny and I wish he wouldn’t. But at least it pops the tension balloon. To make matters worse, I haven’t worn my sodding sunglasses since I came on board. Now I’m going to have to try and find the things and wear them for a while — fake Ray-Bans Mum got on the cheap from Poundland. Just perfect.

I virtually run below deck and throw open the door to my room. Jen is sitting on the side of the bed, looking startled by my sudden return. On her lap is a folded sheath of lined blue paper covered with handwriting. The envelope by her hand is labeled To Mum and Dad. Before Jen can react, the top sheet blows toward me in the draft from the door and I pick it up for her. She snatches it back and flips it over but not before I can make out the words love you forever, Ash.

Jen mumbles something I don’t quite catch and stuffs the letter under her thigh. When she turns to face me, all the blood has drained from her face. She knows I’ve worked out whose parents it was addressed to. She’s reading Ash’s mail? Why?

“Don’t tell Ash.”

I’m disgusted. The envelope is still on the bed near me. I pick it up and wave it at her. “Seriously? Why shouldn’t I? What are you doing with this?”

“He’d never forgive me …”

I start rummaging in my bag for my sunglasses. “Could you blame him? It’s probably something personal. I can’t believe you’re even looking through his —”

“You don’t understand! I don’t do this kind of thing … ever …”

To my shock, tears well up in Jen’s eyes. I sit down next to her, watching her twist the front of her blouse into a knot, undo it, and twist it again, over and over.

“Stop.” I pull her hand away gently. “Why don’t you tell me what’s going on?”

Jen retrieves the letter and places it on her lap again. “I’ve had it for a few days. It’s taken me this long to get the nerve to look, and you came in before I had a chance to read anything.”

“Good. But you’re not making any sense. Why are you trying to read Ash’s mail in the first place?”

“It’s not his mail. It’s the letter every soldier writes before they go to Afghanistan. You know … In case I die …”

No wonder she’s worried that Ash will go ballistic. Who wouldn’t? I can’t help a touch of sarcasm. “Great. I was worried it was something important.”

Jen just looks at me.

“What’s it doing on board?” I ask. “He’s not in combat; surely he doesn’t need to keep it anymore.”

Heavy tears drop onto the sleeping bag. “Since he lost his legs, Ash takes this letter everywhere. There’s something in it. Something he doesn’t want me to see. Recently he’s been talking about ripping it up, and if he does, I’ll never know!”

“So you went into his cabin and ransacked his things. Nice. That’s really going to help things.” I give her a dubious look.

“I know it’s wrong, but you need to understand — I’m desperate. Before Ash was blown up — while he was still in training — we were talking about getting engaged, but when he came back from Afghanistan he just closed down. I need to understand why, and I know there will be some clue in the letter. I just know — he wrote it the day before he went. You think about things differently when you know you could die. You say things …”

“Why don’t you just ask him?”

“He won’t talk about it.”

“So you shouldn’t look — give me the letter.”

Jen’s shoulders sag. She knows I’m right, so she pulls it out but she freezes halfway to handing it over. Her eyes are fixed on the top page, which is covered in Ash’s loose freehand. We both see what the middle paragraph says before I snatch it away: Mum, you’ll see Jen, and I won’t have been able to tell her yet, so don’t repeat any of those things I said. It doesn’t matter now anyway. Just tell her I love her …

I stuff the sheets back in the envelope before either of us can read more.

All the life has gone from Jen’s eyes. She looks at me bleakly and then curls into a ball on her bunk, burying her face in the crook of her arm. Her muffled voice cracks when she says, “Promise me you won’t tell anyone.”

“You need to make him talk about this. He’s going to find out that the letter’s missing sooner or later, and this could be the perfect opportunity to get him to open up. Hey, if you promise to try, I promise I won’t say anything — how’s that?” She doesn’t answer me, so I stuff the letter into the end of my rucksack, the compartment that still has a lock on the zipper. Jen lifts her arm off her face and follows my every move. “In the meantime I’m going to lock this away. Don’t look at me like that, it’s for your own good!”

Jen rolls onto her back and wipes tears off her glistening cheeks. “You’re right. I’m being stupid. He was probably stressed when he wrote that. I should talk to him — if we can ever get any privacy on this thing.”

I’ve actually found my crappy glasses in the same compartment. I try them on. For the first time since I’ve known the girl, Jen actually offers me a genuine, friendly smile — like she’s grateful to me. I really feel for her.

I sit on the bed and give her a hug. When we pull away, I pose and look at her from behind my sunglasses. “Well? What do you think — tacky or what?”

“Well … they are way more shabby than chic. Where do you shop, Poundland?”

Cheeky cow. I laugh with her, but inside I’m all messed up. I’m wondering what I’ve got myself into. All my life I’ve been a loner, and now I’m trapped in a confined space, at sea with five other people, getting drawn into emotional stuff I don’t even want to think about.