05:35, Firstsol 12th M5, 2226

To be alive is to be hungry.

Not the passing hunger pangs of a miner clocking off work, safe in the knowledge that dinner will bring satiety. No, my hunger is different.

It gnaws at my heart. It dulls my senses and makes my mind knot like an eel. Hunger bends and twists me, luring me into depravity. I haven't fed for four sols, and my very soul is unravelling.

The city's air filters are faulty again. Droplets of salty drizzle bead on my jacket. Careful to retreat into the shadows whenever a warden passes, I snake through the market's back alleys, past dumpling vends and makeshift shops constructed of sagging tarp and boxes.

Every sol I tread the same tired pathway from my pod to the hospital, and every sol I hijack that pathway by a brief stop at the Kida Biotech building. It looms over an entire eighth of the city's dome, so exquisite that it disgusts me. The building looks like it's been freshly plucked from Earth and dropped at the Solar System's Edge by Shiva's own celestial hand.

Three storeys of curved brick, mortar and glass, an exotic gem shining in the city's mire of grey recycrete and steel. How many millions of Rupees must old man Kida have spent bringing bricks and mortar, of all things, from Earth to Eris? As if we need any more reminders of the Kida family's immense power out here on the Edge; we're all surviving on the back of Kida technology.

Each step closer to the building's great shadow has sweat pooling on my lip and soaking through my uniform. I've approached the building so many times before, but I've never held my nerve for long enough to make it through those glass doors. Through rain-streaked windows I can make out clusters of svelte Kida Biotech employees in azalea-pink suits with cinched waistlines; busy workers in a hive. Occasionally one of them peels off from the throng and scurries through the foyer, disappearing into corridors beyond a glass atrium.

Proximity to the bricks triggers my lenses. The Kida Biotechnology logo appears on my retinas in 4096-pixel brilliance. Megumi Kida's smiling face follows, and I scramble to mute my earpiece.

A willowy beauty in her thirties, Megumi Kida tilts her head and mouths her broadcast, all furrowed brow and earnest smile. I don't need to hear her voice to recognise one of her public health statements, the same as her father's before he retired, reminding Eris residents to stay warm to keep our metabolic brain implants — our meatware — in optimal condition.

As if the domes of Eris-1 are ever anything but warm, the temperature at a perpetual twenty degrees with precisely twelve hours of artificial sunlight each sol. As a child I'd wondered how the people of Earth tolerated seasonal changes in light and heat, but twenty-five years of hunger on Eris has me craving sun and monsoons, or indeed any distraction from constant starvation. Megumi's pretty face disappears from my retinas in a wash of flickering pixels, and my lenses fall to rest again.

In my early teens I'd tried to end my eternal hunger by starving myself to death, only to break down after five sols and feed ravenously. Nothing has changed since; I trudge from the hospital to my pod every evening, saving my energy and ignoring the maddening pangs in my bones. Some days I don't exist; my bed becomes a coffin and I half-expect that I'll fall asleep never to reawaken. After five sols the miasma of hunger becomes too thick to escape from. Then, I limp deranged into the city and feed under a cloud of gluttony and guilt. Whatever pitiful attempts I make to outrun it, hunger always catches up.

The iris scanner on the building's glass door glows red as I approach. I should have discussed my rare metabolic condition with Kida's scientists years earlier. Perhaps they'd find a way to fix my meatware; they'd cure my perpetual hunger, and this tired daily ritual of walking up to the red brick entrance only to flee in cowardice would be over. Megumi Kida herself might be curious about my condition and want to meet me. I doubt that there's anybody like me in the Solar System. Perhaps she'd take an interest in me and introduce me to her father as a bionic curiosity.

I crush the reverie before it can carry me away. A far more likely outcome is that Kida's biotechnologists will ask questions about what I eat — questions that they won't want to know the answers to. Then they'll report me to the wardens, and Holy Shiva knows what they'd do to me. The thought has my head swirling in hot panic. I run from the red bricks, the iris scanner dimming in my peripheral vision as I flee.

My flight takes me through the alleyways that criss-cross the immense geodesic dome of Eris-1's market, far from the busier bars and shops usually patrolled by wardens. I've moved between Eris's cities often enough that nobody suspects what I am, but it's only a matter of time before the wardens catch me. Adrenaline abates once I seek out the darker alleyways of the market. My skin crawls with hunger. Perhaps it's time to move to another city. But first, I need to feed.

The dome's colossal luminaires mimic a perpetual noon on Earth: brilliant enough to denote daytime, yet too dim to evoke the sun-soaked warmth of a home planet I've never seen. Haggard miners mill to and fro around me like so many cargo beetles, haggling over lens accessories and stuffing samosas into hungry mouths at vends. Weighed down by their own worries they barely look my way as they hurry towards the outskirts where the neon signs of Eris-1's dive bars and shade dens flash bright. Nobody ever takes notice of me. Nobody knows what I am.

Familiar waves of light-headedness from my creeping starvation wash over me. I duck into a promising alleyway. A woman with a dirty face lies sprawled in a dark corner, boxes and detritus shielding her from the acidic drizzle. Tattoos of a flowering vine adorn her forearms. Her breath stinks of shade. She blinks at me with unfocussed eyes.

She's perfect.

"Are you ill?" I creep closer, unfastening my medical bag. "Do you need food?"

The woman flinches at the movement and hauls herself further into the corner, dragging a bloated leg behind her. Her shins are mottled with welts: the late stages of radiation sickness. Our meatware renders everyone on Eris radiation-resistant, yet this woman is the fifth person I've seen bearing signs of radiation damage this month.

Shade-eyes peer at the shadows cast by my hood, as if trying to identify me by my lips and beard. When convinced I'm not whomever she's hiding from, she eases. "Got shade? I got money."

"Your leg looks bad. Here." I hold out a crumpled samosa. "Eat this. Your meatware won't fix your infection if you suck shade and don't eat."

Her eyes scan my cyan doctor's uniform. Sure that I'm not a threat, she sits up on stiff limbs and snatches the samosa to her chest. She begins to nibble at it with furtive pecks. "I'm not going underground. I can work."

She's weak. She'll barely notice me feeding on her. Besides, I'll be gentle. I won't take much. Only what I need.

"Your meatware is faulty. Looks like you're taking radiation damage. You need to go underground."

She raps grazed knuckles at her temple. "Nothing wrong with my meatware."

"You got somewhere safe to go?"

"Don't call the wardens." The woman inches up the leg of her tattered peacock-green trousers, the seam ripped wide to accommodate the bloat. Dirty nails rake over a cluster of red sores. "I'll be well soon. The mines will want me back to work."

Large enough to create its own clouds, the geodesic heavens of the market open. Fizzy mist turns into a downpour. The woman sinks back against the wall, falling deeper into shade-brain. Perfect.

I reach out my hand. Tingling fingertips hover at her shin. "Let me look at those sores."

I'm evil. A monster.

But the hunger.

"I'm all right. You don't have to..."

"I can bandage them for you."

She flinches away from my approaching fingers. But the look in her eyes begs me for contact, for kindness, for relief from eternal Eris.

I'm disgusting.

But I'm so hungry. I'll only take a little. Only what I need.

A tentative fingertip brushes along the woman's mottled shin.

Holy Shiva. The bliss.

Ecstasy shoots through my finger at the first touch of skin on skin. Pure, unfiltered ecstasy.

She sits still at first; maybe the shade is masking the effects of my feeding. Then, she stares up at me with wide betrayed eyes. Her fingers scramble in the dirt of the alley, her mouth agape in a horrified oh.

I press a second finger to her leg. Shade-breaths quicken. Frantic eyes beg me to let go.

But I'm safe. She can't see my face under my hood. I'll only take a little.

The bliss. It feels so indescribably good.

After four sols of hunger I'm powerless against the rush of feeding. Try as I might, I can't hold back. If only I could take it all from her. It's been years, decades even, since I last fed until I was sated. I want so desperately to drain every drop of her energy.

I want it all.

Terror-stricken eyes lock onto mine, before closing in a faint. She slumps against the wall. My fingers slip from her leg.

I've been greedy. I've taken too much. She'd been weaker than I'd expected.

"You!"

I snap my head up to see the steel-grey uniform of a warden stalking out of the shadows. Their kholed eyes gleam with triumph.

Meaty fingers inch towards the pulser at their belt. "You selling shade?"

I lunge out of the alleyway before the warden takes another step. Their pulser beams diffract around the wall towards me as I race away from the market, but they're too far away to do more than send my jacket billowing out as I flee.

I hadn't meant to take so much from the homeless woman. I hadn't realised that she was so weak. But I'm safe. I'd had my hood low over my head. She won't identify me. And if she does, the wardens would never believe a shade-addled miner with broken meatware over a doctor. Would they?

She'll be OK. Just a day or two of exhaustion, and she'll be OK. She was breathing just fine when I left. Wasn't she?

Holy Shiva-Shakti. I'm a monster, a nightmare. How many more of Eris's sick and dying can I abuse before someone finds out?

A steel-grey uniform looms out of the market's drizzle. My pace doubles. I need to get out of this city.

I'm an abomination.

An energy vampire.

A parasite.