The first struggle of the day was all too familiar to Alexa. Even with the other her sitting on the edge of the bed, beckoning her up, her mind wanted no part of it. Every fibre of her being wanted to curl back up under the covers and drift back off to sleep. Doing that would be so easy, compared to what was coming.

She frowned. How did she-

“Oh good, it’s coming back,” the other her said, clapping a little. “Now it’s best if you get up. They’ll be waiting for you.”

She was right. They were waiting on her. To go to sleep now would be a major letdown, on perhaps the most important day of the great journey. No, she thought. The greatest day so far. She had a job to do.

Alexa hopped off the bed and headed for the small door in the corner of their little room, pulling it aside and stepping into what little space there was for a shower. It was only when she undid her robe and tossed them out of the cubicle that she realised that her outstretched arm was not her own. She drew it in, closer, and examined the callouses along the length of her fingers. It was a robust hand, unfit for the delicacy she always thought her painting required. Amusingly, it was also a few shades lighter than her.

“So this is who you are.”

“Who’s who?” the mirror of her asked, leaning in the cramped doorway of the utilitarian bathroom.

“I’ll be as quick as I can.” Alexa pulled the cubicle closed, and then turned on the water. It was warm, and soothed her soul as it washed over her face.

When she opened her eyes, she was in front of a battered metal console that was her workstation, tapping at a glass-covered meter, watching its needle wobble in place. She looked up to find a large window overlooking the ship’s reactor, a massive tower bridged to the hull on all sides, glowing a faint blue from the little bit of harmless radiation that leaked out of its fluid-filled torus core.

“Commencing test!” a familiar voice called from across the room.

Alexa turned, expecting herself again, but was instead met with Aerin in a uniform not unlike the one she was wearing, her hand resting on a lever that jutted out of another console. “Aerin?”

Aerin blinked. “What was that?”

“Uh, nothing.” Alexa turned back to her console. “Ready when you are.”

Aerin leaned into a microphone on her console. “Temporary hold, I was distracted. Let’s go again on my count.”

Alexa’s hand rested on a new button wired up to the console, one she had set up over the past month. The prospect of the test run was absolutely terrifying in its own way, but the idea of it failing was worse. There was no telling what her lord would say or do, and she didn’t want to find out either way.

“Three!”

Alexa licked her dry lips.

“Two!”

She could feel her finger twitch right on the button. One press, and the injector would do its thing.

“One!” Aerin pulled the lever, causing the heavy shutters above the windows to unfurl, rolling down in segments until they slammed into place against their locks against the floor. “Do it!”

Alexa jabbed the button down, and there was the sound of heaving metal, and something let out a shrill screech from beyond their protection. The screens on her console flashed, warning her in their custom-made glyphs that the reactor’s output was unexpectedly spiking. It was expected of course - that was exactly what was supposed to happen when you injected a fresh batch of antimatter - but she kept her eyes on the dial. The new thermal plates had to hold. They had to. The team had spent thousands of hours laminating them with what little they had, building up layer by layer until it could take the increased energy density inside the plasma. Now it only had to hold for a couple of minutes, enough for the transitional energy to reach its peak, and then they were home free.

“Almost there!” she shouted over the roar of the reactor’s protests and the warning alarm.

The ship around them was beginning to shake. It had always vibrated from the force of its propulsion, but this rattling made it into her bones. She git her teeth to prevent them from chattering, and locked eyes with the timer in another part of the console.

“Almost there…”

A second set of alarms kicked off, but she simply shook it off. The containment field was fine, and the torus was fine. She’d have to rewire that part later…

“Terminating!” Alexa hit the button again, and like a breath that was being held, the ship itself groaned out a sigh of relief. The shuddering stopped, and the alarms went silent.

Aerin pushed the lever back up, causing the radiation shielding to fold itself back up, piece by piece. The glass beyond was untouched, and aside from one of the actuator arms hanging above the reactor being lowered into position, the entire chamber was untouched. There was no damage, and that was all she could ask for.

The control room erupted into applause, and as she looked around, she found that everyone there had no faces. The fronts of their heads were simple gaping holes, almost like the sun within the yokai’s realm.

“Well done.”

Alexa turned to see Aerin next to her. “Yeah. Should be stable enough to switch to the new fuel.”

“Who wants to tell him?”

Alexa put a hand on her shoulder. “It’s your achievement as much as mine. We’ll do it together.”

Her pen clattered to the floor, and she knelt to grab it.

“Very impressive. This is truly a day worth celebrating.”

The new voice made Alexa shudder. She hadn’t heard his voice in literal years, and yet, the recognition was instant. Still, she didn’t look up. To do so without invitation would be doing her lord and her station a great disrespect.”

Aerin knelt beside her with the same reverence, her eyes pointed at the floor. “Your praise is well-treasured, my lord.”

“Rise.”

Alexa slowly got to her feet, and met the man before them, a spitting image of her father. The breath left her immediately, and her legs felt like jelly.

Her father sat down in the captain’s chair, which was covered in fine golden cloths, each a tribute from a different member of the crew. “Will you progress with this…upgrade as soon as you can?”

“I- We will,” Alexa said. “By night’s end, we will have moved over to the more efficient fuel source.”

“Your names will ring out across the stars,” her father said. “You will be richly rewarded, my friends. For now, rest.” He waved his hand in dismissal.

Alexa could not help but bow before turning to exit the bridge. Her mirror self waited outside, smiling for her.

“Told you it would go well.” She waved at Aerin as she climbed down a ladder.

“You never told me that.”

“I tell you it all the time. You wouldn’t be standing here if I didn’t mister. All that guilt and self-pity would eat you alive.”

“Guilt? What guilt?”

“For what you did, duh.”

“What did I-”

In the next blink, mirror Alexa was gone. They were back in the control room, but this time, she was in front of the windows themselves. The core thrummed like usual. She glanced back. A faceless technician was in her place, but Aerin remained on the lever.

“No need to lower the shields,” Alexa said. “I kind of want to see this.”

“Unless it explodes?” Aerin joked.

“Then sure, drop it. But it shouldn’t go that far.”

Aerin chuckled. “Whatever you say, boss. Control is ready.”

“Venting is ready,” said another voice over the intercom. “Good luck.”

“On my count. Three!”

Alexa turned back to the reactor. The injector arm was already lowered, and all that was left to do was to increase the transitional energy again. A new reaction to overtake the old, enough to sustain them at least another decade.

“Two!”

Alexa leaned in so close that the tip of her nose made an oily spot on the hardened glass.

“One!”

Something flashed silver in the port of the injection machine. “Wait, I think we should-”

The noise of the reactor’s injection, louder now that it wasn’t dampened by the shielding, drowned her out.

“Reading stable!” the faceless person in her place said.

“You’re clear to flush,” Aerin said over her microphone.

Alexa waved her hands. “Stop! Something’s not-”

Honk.

The whole control room evidently heard the new sound because they were now all looking past her. Alexa followed their gaze to the injector arm, and its connection point was on. Small jets of plasma leaked from it as it shuddered, harder and harder, the antimatter payload threatening to dangle out of its socket.

“Abort!” There was no telling if it was Aerin or herself screaming. In all likelihood, it was both.

She looked back once more as the shields began to drop, and a blinding white light consumed the room.

When she came to, it was on her bed one more. She closed her eyes, but the flashlight bean pierced her eyelids, forcing her to roll over.

“Are you really going to sleep for the rest of the year?” It was her own voice. The mirror. “It’s not good for you.”

“What’s the point?” Alexa threw the covers over herself.

“The point? This isn’t you! You made a mistake! Our lord stands behind you! The reactor functions!”

“But you see how they all look at me.”

“They will see, soon enough.”

“They won’t.” She knew it would never be enough. In an ideal world, the released plasma and all the radioactive byproducts made in the ring would have been trapped in the reactor room. At most, the control room would need to be scrubbed before it could be used again.

And then one of the cows got sick. Within months of the symptoms starting, it was dead. A malignant growth in its gut, one of the doctors had said. Nobody knew how long it had been there, or if any of the other livestock were the same way.

Nobody knew how much of it made it into the food.

In a ship of three hundred, rumours spread like wildfire. That it was her carelessness that caused the explosion, that she had failed to contain the breach. There was, of course, nowhere else the poison could have come from. Aerin took the brunt of it too, enduring the accusations of a growing mob before their god had stepped in and dispersed the crowd.

That was the first time she had seen the values of a god conflict so clearly with its followers. There were no comforting words that would wipe away the truth that took hold: the radioactivity and the heavy metals could be in all of them, untold damage already done to their biology. Every denizen of the ship was a ticking timebomb.

She rolled back over, to see her own back. The robe her mirror self wore was loose on account of how skinny she had become over the last year and a half. Bundles of tissues littered the bed and the floor, stained with the blood they were now both coughing up, old and new.

“Hey,” Alexa said, tapping herself on the shoulder.

Her mirror self rolled over, gaunt in the face, her hair barely clinging to herself. Still, she forced a smile. “Hello, handsome.”

It was impossible to ignore the raspiness in her voice, but Alexa just smiled. “You don’t have to get up today. I’ll get the rations.” She climbed out of bed, trying her best to ignore the pain in her side. In their tiny flat, carved out from the barracks, it only took a few steps to get to the door.

“Wait…”

Alexa paused at the door.

“Take me.” Her mirror self tried to get off the bed, but her legs shook, and she sat instead, coughing out more flecks of red that stained her nightgown. “I haven’t been out in so long.”

Alexa sighed. “It’s not safe. You know what’s out there.”

“Safe enough…with our lord’s protection. Carry me, won’t you?” There was an earnest look in her eyes as she looked up.

“...okay.” She lowered herself to bed level, and in one fluid motion, scooped herself up in a bridal carry.

Her mirror self giggled. The sound was from a better, simpler time. When the news broke that they had been selected for the great journey, to ascend past the filth and sin of humankind, it had been cause for celebration. They were to cross the stars to a new home, and with her work on the reactor, it would have taken two decades, at most. At 97% of the projected power production, that timescale was manageable. Trivial, even, despite the damage to the chamber.

But alas, it was not to be.

When the doors opened, Alexa immediately felt the skin of her cheeks burn. The radiation in the core, after all these years, had only built up. It was lethal the moment she was exposed, but then again, it had been lethal for a while. One way or another, they had known it was coming. All that was left was to watch those you love fade away, bit by bit, another victim of an invisible killer that had them all in a list.

Each step she took forwards took immense effort even though the body in her arms weighed almost nothing at this point. Despite what he thought her role in this catastrophe was, she was forever thankful to the last embalmer for preparing her mirror’s corpse, to allow her to find peace in the dark. It was a little easier to swallow than she expected, considering he had Steven’s face.

But Alexa would not have that same luxury.

It felt like an hour before she made it to the edge of the walkway. The railing had been torn off its mounts a long time ago, when Aerin had been the first to take the plunge. She often wondered if it was to atone for her involvement with the incident, or to merely even the scales and spare Alexa the wrath of the crew. Or perhaps, she had seen the same thing Alexa saw now, standing in the same position.

Despite modifications to the machine, Alexa could never forget where the damaged arm had been. Directly above it, in the wall of the boiling hot chamber, one of the filters was broken. They had checked the room over before the final deployment, and as far as she could tell, it hadn’t been. The grating was smashed in, the dents small enough to be some kind of handheld tool, wielded by a single person.

But there was nobody left to call saboteur. Alexa knelt at the edge, and for a moment, considered muttering a prayer to their lord for guidance. But it left a bitter taste in her mouth, or perhaps that was blood - mist of her ability to taste was gone, and slowly, her vision was fading.

She looked up at the ornate sarcophagus suspended by chains in the middle of the reactor ring. At that moment, the mummified remains of her copy fell, slipping out of her useless hands, tumbling down to join the masses of the similarly embalmed. For a second, she thought she still saw Aerin down there, blankly staring up at her.

What use was a god in the face of inevitable death? Why had they been chosen so succinctly by him, only to perish in a manner most excruciating?

The other Alexa did not answer. Death, it seemed, had taken even that from her.

A curse was on her lips as she collapsed, and the world, mercifully, went dark.