He pushed the bowl aside and reached for the vitamin solution. Alaya would warn him if his medical results had deteriorated. He took a gulp and set the bottle aside. Where was the AI? She played his alarm later than usual but didn’t come to greet him. Alaya hadn’t joined him for breakfast, more of a lunch now, with the usual update on the station. Was she dealing with the other human problem? His arm twitched – Donghyun balled it in a fist and thumped against the tabletop. How could it have occurred in the first place?

His eyes followed the slender figure moving frantically on the screen. There was still plasticity and grace to her movements, of almost mesmerising quality. Donghyun shook his head and switched the cameras when she entered the lift. As the numbers on the level panel grew, his skin cooled rapidly, acquiring an even whiter hue, his breath turned shallow, and another quiver ran through his limbs. What had the woman been doing on the hangar level all this time? She must have arrived recently. His heartbeat sped up as he watched her exiting on the middle living level, just under the refectory he was sitting in. What was she looking for? Him? His lab? The prospect of confronting another living soul exacerbated his tremors.

Donghyun opened another window with the station’s performance. The system had warned him about the temporary glitch in the AI systems when he woke up. It was an automated notification, which did not require direct interference from Alaya. That was how he discovered the unwelcomed guest in the first place – checking the station for any external damage or switched-off sections. Everything seemed to be working perfectly at the moment, which only raised the question – why was not Alaya reporting the intrusion? He could not believe his assistant was involved – the AI knew and shared his views on how this research should be run. Besides, the station had been cloaked all these years. Unless, the glitch caused the shield to malfunction and a rogue ship docked with them. He took a few hurried gulps of the vitamin solution, the bottle nozzle clattered against his teeth.

He wiped the spilled liquid off his chin and returned to the tablet, accessing the camera records. The ship would not be able to dock without Alaya’s permission – they would need some serious tech and coding to override the AI. But that could be the source of the glitch. Only a Raj-3-ian black-market gang was capable of that. Had they been looking for Cheonsa specifically? The station had been an advanced research facility before Donghyun and Alaya went dark. He observed corridor after corridor but couldn’t see another soul. In fact, even the woman didn’t appear until a few hours into the station’s early morning, and she didn’t exit from the hangar door. He rewound further and further back, casting an occasional glance at the cameras’ clock at the bottom. Then suddenly the screen went grey with static. The earlier videos had been erased. But was it the glitch or the pirates who did it? What if Alaya had been damaged by them?!

Donghyun checked the virus lab – there was no record of unauthorised entry, the biohazard storage and the medication lockers looked intact. It wasn’t like the gangs to leave things tidy and pretty after themselves. And why did they leave the girl behind? Was she a spy? Not in that outfit, definitely not. Someone they wanted to dispose of?

The screen was showing him the hangar level an hour previously; the woman was entering the Maze Test Room. He switched the feed and watched her disappearing among the glass partitions. Donghyun started the programme responsible for the Maze sensors. It launched automatically the moment the Maze was engaged, and lucky for him no one overrode it. The Room was a later addition to the station, while it was still filled with people. They used mutated clones to check the secondary contagion process; using the visible mutations helped them understand whether the new strain of virus tackled the same areas or different. Currently, it was giving Donghyun only the heightened pulse of the woman, the dilation of her pupils – she was frightened. Whoever dropped her here didn’t prepare her for the encounter with their monstrous clones. Donghyun was surprised himself to see that they hadn’t been liquidated, but then he hadn’t been to the hangar level in years. Likely, Alaya’s programming required to maintain the creations, or she hoped to find more use for them.

More data came from the adjacent infirmary. Donghyun was relieved to see Alaya’s direct commands to treat the patients. So, the AI was functional, and hopefully sorting the problem already. He might not even be needed. Then, he remembered that the woman was just one level down. Was Alaya trying to make the girl comfortable? His head was spinning from all the inconsistencies. If the woman had been kidnapped, someone would be looking for her and they might come across the station. What if someone dumped her here because they suddenly discovered she was infected and were scared to catch the virus? If they had left her in an escape pod and it floated close to Cheonsa, the woman could have used the special protocols to dock. Then Alaya might consider this as an opportunity…

He dug the nails of one hand into the back of the other, leaving deep blue crescent marks on the poreless skin. He thought of the negotiations he would have to run to establish the parameters of the experiment, the talks and support he would have to give throughout it, the connection he would have to build with this person. The ghosts of contorted faces floated in his mind’s eye. He felt his head being crushed in the vice of sudden pain; the aching sensation spread throughout his body as his muscles began to cramp. There must be a way to complete his research without this.

Donghyun shut all the programmes running on the tablet and got up. He would not be curious about the stage of her infection or the mutations, nor about her personal story. She should remain just a spectre on the camera feed.

He left the refectory heading to the lab, making a plan for today’s work in his head. However, when he entered the premises, the first thing he did was to go and check whether all the capsules with the virus and the reversal agents were in place in the storage. Nothing was missing, so he exhaled and moved on to the small womb-printers that were growing test embryos for him. His good mood evaporated as he checked their status. Only one embryo showed a slight growth of the brain matter; the rest remained static, which meant they weren’t going to evolve into proper beings. His teeth clenched, he went to chuck the biomass into the special recycler, even though there was little point in this. He could not engineer more stem cells from the recycled biomass. He swore under his breath. The laboratory here was designed to engineer viruses, not humans; those clones they had were brought from the planet surface. Meanwhile, the small amount of human biomaterial he had was running out fast. If the next batch of embryos failed as well, they’d be at the dead end. The woman on the level below might become the only solution.

He took the container with the stem cells from the freezer and set the empty womb printers to work. At his computer, he opened the latest file with the anti-virus trial, but the diagrams’ figures jumped and made no sense. He gave up and returned to the cameras, finally founding the woman at the observation deck. The shutters were up, but the aperture was closed; the image of a huge blue star was only a carefully crafted arrangement of pixels, yet a very realistic one. He wondered what Alaya was up to as he observed how the sparks on the woman’s skirt flashed in the artificial light, sending a dance of flickers onto those walls that were still in shadows. He stared mesmerised by her shifts and her body language, his hand extending to touch. Donghyun jerked it back and shut the window of the camera, returning back to his diagrams.

He scrolled to the middle section where five different viral genomes were positioned next to each other. The first one was the original unmutated virus to adapt humans to the partially terraformed Raj-3. The last one was the DNA after his intermediate was applied. In between were the three starkest mutations of the original virus – the one that happened in the virus soon after it was applied to humans, the one from the fourth epidemics, and the one he bore within him that made the virus his symbiont. All apart from the first and the last were causing mutations incompatible with life on Raj-3. His virus allowed him to live but it still caused mutations. In his case it was an additional organ, benign in nature but spreading cells like a tumour. Donghyun could not guarantee that in another human being this would not turn into cancer.

He put the data into a simulation; the process of entering and verifying was long and by now unusual. Under other circumstances he would call onto Alaya to do it, but he did not want to distract her. Or perhaps he was afraid if he started talking to Alaya, the topic of their guest would creep into the conversation. He introduced every variety of the virus known to him and prepared to wait. A severe twitch started in his left leg, and he went to prepare the syringe, just in case. The last seizure threw him off the schedule, and he was planning to avoid anything like that in the future. He started sketching the paper to insert the results of the simulation in, then took a break and went to prepare the viruses for the lab tests. The twitches were gaining strength and receding as he went through his day, pretending that there was not another living soul on his station.