'Are you sure this is safe?'

Shadow opened one eye, looking up at the supervising physician. A distorted, metallic guitar riff played in his earpiece. 'For the last time – yes.'

She shook her head and removed the IV cannula from the blood bag that they'd just filled. 'It's just … most people only donate one pint at a time. But we've already filled … four bags?'

Shadow glanced over at Elijah. 'Five.'

'And are you sure you're all right –'

She was interrupted by a knock on the door, and Alex entered the room, wearing her trademark respirator and googles once again.

Alex stared at Shadow and exhaled. 'You're a real team player, aren't you?'

'Oh, please.' Shadow tapped one finger on the venous cannula that he was holding in place. 'You didn't need me at that meeting. And this is a better use of my time anyway.'

Alex crossed her arms and glanced at the blood bags hanging from the IV stand beside Shadow's chair. 'How are you doing this?'

'What do you mean?'

'You're barely three feet tall and weigh … what, 85 pounds?'

'77 pounds.'

Alex's eyes widened slightly, and she walked over, taking the IV cannula and plastic tubing out of the attending physician's hands.' That means your total blood volume is only 4.5 pints.' She stared at him, and horror dawned on her face. 'Shadow, if people lose more than a fifth of their total blood volume, they can pass out from hypovolemic shock.'

Shadow tilted his head to one side. 'So?'

'So?! If you've filled five blood bags, then you've lost more blood than you have in your entire body –' Alex yanked his hand away and pulled the venous cannula out of his arm. 'Dammit, have we been using unit sizes calculated for humans? How are you still conscious? Hell, how are you not dead?!'

'The reason I'm not dead is because I can't die.' Shadow bit back a smile. 'Haven't you been listening to a single thing I've told you?'

'Of course I have.' Alex got down on one knee beside him. 'I have, but this shouldn't be survivable, even for someone like you … How are you doing this?'

Shadow shifted in his chair. He could hear fascination bleeding into her voice. Even though it probably wasn't ill-intentioned, it was still enough to unnerve him.

He materialised the Chaos Emerald, holding it in his gloved hands. The glow illuminated the room, saturating it in a golden hue. Lindsey abruptly sat back in her chair, and Elijah's eyes widened.

'I can use Chaos Control to heal myself.' Shadow's voice was quiet, and he gazed at the gem's facets, as though looking through a prism and into the past. 'If I get injured, I can rewind time and return my body to its original state.'

'So you're replenishing your blood by … rewinding time?' Alex asked.

'No.' He ran one thumb along the emerald's sharp edges. 'Rewinding time takes effort. It's like trying to swim upstream.' He glanced at Alex. 'But accelerating time is another matter. It's like…'

'… Swimming with the current.'

'How astute of you. Have you considered going into theoretical physics?' Shadow muttered.

Alex gave him an offended look.

'I wasn't kidding. You could explain spacetime to GUN's theoretical physicists with fingerpuppets and crayons, and they still wouldn't get it. You've already cleared the first hurdle.'

Alex scoffed. 'I've already sunk eight years into becoming a hematologist oncologist. I think I'll stick it out a bit longer.' Her gaze landed on the Chaos Emerald again. 'So the reason you're able to survive losing so much blood is because you're accelerating your body's natural processes. You're … overclocking your bone marrow.'

The emerald disappeared, and Shadow examined his arm. 'For lack of a better term.'

Alex raised a hand and pointed downward. 'You're looking at the wrong place. Most of those blood cells are coming from your hip bones.'

'I was checking whether the puncture wound in my arm had healed yet,' Shadow retorted.

'Sure, sure.' Her words were light-hearted, but her eyes belied concern. 'But we need you to take care of yourself. If you keep overclocking your body like this, then it can lead to bone marrow failure.'

'I know my limits. And even if I overexert myself, I can still accelerate my own recovery –'

'You don't understand, Shadow. We need to keep your bone marrow intact.'

Unease trickled down Shadow's spine. 'What?'

Alex looked over at Lindsey. 'Can your son hear us?' she whispered.

Lindsey shook her head. 'He can't hear a thing.' She shot Shadow a look. 'A byproduct of listening to death metal, apparently.'

'Speed metal,' Shadow corrected.

'Speed metal?' Lindsey repeated. 'Seriously? That sounds like the name of a zone on one of those godforsaken islands –'

'Mrs Tower,' Alex interrupted. 'We discussed Elijah's case at the multidisciplinary conference.'

Lindsey's expression changed so swiftly that Shadow nearly flinched. She knotted her fingers together. 'And?' He hadn't known that it was possible for someone's voice to sound so weak.

'We're going to perform an allogenic transplant.'

'But …' Lindsey's fingernails dug into the back of her hands. 'You've already tried that. You've already tried everything.'

'We haven't tried using him to do it,' Alex said quietly, tapping a finger on one of Shadow's inhibitor rings. 'And that's what's going to make the difference.'

Shadow raised one hand to his earpiece, lowering the volume until all he could hear was the tinny echo of the same song coming from Elijah's headphones. 'Alex …' His voice was even and measured, but that was only because of his best efforts. 'Do Elijah and I even have remotely similar HLA types?'

Lindsey stared at Shadow in alarm. 'I'm sorry … Do you even have an HLA type to begin with?'

'I have a human blood type,' he said pointedly. 'Is it that hard to believe that I also have human leukocyte antigens?'

'… Because you're not human.'

'You've got to be kidding me,' Shadow muttered. 'Professor Gerald was creating artificial replicas of souls and infusing them into his creations, yet you're getting hung up on whether I have a MHC code or an HLA type –'

'Look,' Alex said, interrupting them both. 'It doesn't matter whether Shadow literally or functionally has human characteristics – what matters is that he has them in the first place.'

'You still haven't answered my question,' Shadow said. 'Do Elijah and I have compatible tissue types?'

Alex gritted her teeth. 'They're … similar.'

'If you're going to be injecting him with my bone marrow, then "similar" isn't good enough.'

'I know that.' Alex pushed up her goggles. 'We may not understand how all of this works … but we're hoping that the fact that you have an HLA type in the first place means that it will function in the same way that a human's would.'

Shadow's eyes widened slightly. 'Damn it.' He covered his mouth with one hand, masking a wary smile. 'You are unhinged, aren't you?'

Lindsey looked confused, and her voice shook when she spoke. 'What are you talking about?'

'You can't change your HLA type,' Alex said. 'It's genetic. You also need a 7/8 HLA type match when performing an allogenic transplant.' She took a deep breath, steeling herself. 'But when someone undergoes a bone marrow transplant … It can change their HLA profile by replacing their bone marrow with donor cells that have a different HLA type.'

Lindsey dug her fingernails into her palms. 'I'm sorry. I know you're doing your best to explain, but this is a lot to take in, and I –'

Shadow leaned forward and snapped his fingers in Lindsey's face, startling her. 'Keep up, would you? They're going to inject me with your son's bone marrow and cross their fingers that my HLA profile will be a match for Elijah's by the end of it.'

Lindsey was so shocked that her hands went limp, falling into her lap. 'Is that safe?'

'Sure –' Shadow scoffed and said, 'They're going to be injecting cancerous myeloid tissue directly into my bones. Of course it's not safe.'

'But it won't be fatal,' Alex said. 'Shadow, you were the one who said that nothing we can do will kill you. You should be aware that your little speech at the multidisciplinary conference sparked quite a few imaginations. '

Shadow gave her a filthy look. 'You're the head of hematology. Don't pretend as though you're not also talking about yourself.'

'Believe me, I'm as guilty as the others. I also know that this is a lot to ask.'

'You're not asking. You're telling, at best.'

'Couldn't we …' They both turned to look at Lindsey. She hesitated. 'Couldn't we do this the other way around? What if we changed Elijah's HLA profile to be more like Shadow's?'

'No!' Shadow snapped. 'We're trying to save him, not kill him!' At the stunned look on Lindsey's face, he forced himself to lower his voice. 'The more dissimilar our HLA types are, the more risk there is that Elijah will get graft vs host disease when we give him my bone marrow.'

Lindsey turned white. 'No. Oh, no.'

Even though they were only talking about a hypothetical, Shadow felt panic begin to stir in his chest. 'Your son's immune system is completely shot, and my cells are incapable of dying. If we gave him my bone marrow now in an attempt to change his HLA profile, then he could get GVHD … and my white blood cells would tear him apart from the inside out.'

'Which is why that's not what we're doing,' Alex said, giving Shadow a warning look. 'We're going to take bone marrow biopsies from both of them. Once we've simulated interactions between the samples in a lab and tested for adverse outcomes, we'll take Elijah's bone marrow and give Shadow an allogenic transplant, forcing his HLA profile to match Elijah's. After that, we can use Shadow's bone marrow to give Elijah the full allogenic transplant that he needs.'

'Putting aside the fact that you're going to inject me with literal cancer and hope for the best …' Shadow's brow creased. 'The changes that bone marrow transplants cause to HLA profiles aren't temporary. They're permanent.'

'We're aware of that.'

Shadow raised one eyebrow. 'Even if I agree to that, GUN won't. You're out of your mind if you think GUN will let you make permanent modifications to one of their bioweapons.'

'Our current plan is to extract your bone marrow and reinfuse it later, restoring your original HLA profile. But we can't guarantee the final result.' Alex ran her thumb around the edge of her coat sleeve's cuff, staring at the linoleum as though it would spell out the answer if she looked for long enough. 'If only …' Her eyes widened, betraying a faint glimmer of hope. 'If only we could rewind time … and restore your body to its original state instead.'

Shadow froze. Then he exhaled through his teeth. 'That's one way of getting around GUN's restrictions. They can't object to something that will have never happened.'

'In that case … Do you think you can do it?'

Shadow tapped one finger on the armrest of his chair. 'How long does it take for an HLA profile to change?'

'Several weeks to a few months.'

Shadow nodded, resisting the urge to scratch at the healing puncture wounds in his arm. '… I can accelerate the engraftment.' Ice began to pool in the pit of his stomach. 'But doing that will also accelerate my immune response to the literal cancer that you're going to be injecting me with. And the more that I accelerate both processes, the more energy I'll need.'

'What if you spread it out over time?'

'We don't have time. None of us do. The longer I take to do this, the less time you'll have to use me to help other patients.' He got up, wishing that he had his jacket so he could stow his hands in its pockets. He began to pace. 'But after the engraftment is over, and you've transfused my altered bone marrow to Elijah, I'll need a massive amount of energy to rewind time by several weeks or months in order to return my body to how it was.'

'So it's not … possible?'

Shadow turned and looked at her in bewilderment. 'Of course it's possible. I never said it wasn't. I'm talking about logistics here.'

Alex got up and walked over to him. 'But even if it's possible, are you sure you want to go through with this? You're talking about something that most people would have weeks or months to process, but you'll only have mere hours. Knowing that you'll survive won't make the experience any easier, and you'll remember everything –'

'It can't be worse than what I've already gone through.' Shadow crossed his arms, and his brow creased. 'Why are you looking at me like that? You found it – the solution you were missing. What are you waiting for?'

'I'm waiting for you to back out … because I can't believe that someone would put themselves through something like this willingly.'

'I …' Shadow trailed off, noticing how rigid her arms were. He stopped time, and a green glow swept through the room. He walked behind her. Alex's fingers were crossed so tightly that they had turned white. Something twisted in his chest.

He walked back to where he had been standing and let time resume. 'At least I have a choice. For once, I have the chance to –'

His words were cut off when she dropped to her knees and threw her arms around him. He helplessly held his hands in the air, turning away so her goggles didn't graze his face.

'Thank you,' she said, and her voice was muffled.

'I haven't even done anything.'

'I know.'

He looked down and saw that one of his quills had cut a line in her surgical scrubs. '… You're going to have to go through decontamination again.'

'I know.'

He lowered his head and lowered his voice. 'There's no guarantee that this will work out in the end, even if we do everything within our power.'

She squeezed tighter. 'I know. But you're the best chance we've got.'

Shadow removed her arms from his shoulders and stepped back. Lindsey opened her mouth to speak, but he cut her off immediately. 'Save it. Even if you were capable of talking me down, it's already too late.'

'I wasn't going to.' Lindsey cleared her throat and blinked several times. '… You know, as much as Abraham sings your praises, he still complains about you behind your back.'

A half-smile flickered on Shadow's face. 'I'd be shocked if he didn't.'

Lindsey smiled weakly in return. 'He always says there's only one person who could ever talk you down from something, and he knows he's not that person.'

'It's not just one person. But there are very few people who could talk me down from something, and neither you nor your father-in-law are one of them.' He attempted to soften his voice, but he didn't know whether he would succeed. 'Don't try to stop me.'

In any other setting, it would have sounded like a threat. And maybe it did, in fact, still sound like a threat. He didn't know whether Lindsey still saw him as the monster that Abraham had described him as. He didn't know how anyone at this hospital truly saw him. Maybe they saw him as an argumentative asshole with obligations to fulfill. Or maybe they saw him as a misguided altruist looking for a second chance. Or maybe they had never seen him in the first place, only catching sight of the shadows he had left behind.

If people wanted to chase shadows, he didn't have the heart to stop them. Because even though attempting to capture a shadow was an exercise in futility … shadows were also supposed to lead you to the light.

There was a swift rap on the door, and Shadow recognised the sound of Iain's cane. He strode over, briefly raising one hand in farewell, and stepped out of the room before Alex or Lindsey could stop him. He slammed the door shut behind him and leaned against it with a sigh.

'… Director.'

'I said to call me Iain, son.' Iain wrapped his fingers around the handle of his cane, searching Shadow's eyes. 'I take it that Alex was telling you about Elijah's case. I wish that we'd been able to find a way to safely reverse the HLA profile changes –'

'We have.'

'We have? How?'

'Spacetime manipulation.'

Iain stared at him for a moment. Then he looked away, his brow knitting together as he became lost in thought. '… Good heavens.'

'You can ask Alex to explain it to you. I …' Shadow winced, holding one hand to his head. He could feel a faint headache growing in the back of his skull, and his heart rate was faster than normal.

Iain looked him up and down. '… How many glasses of water have you had?'

'Water? What water?'

Iain shook his head and heaved a sigh, limping over to a nearby vending machine. 'If it weren't for your personal circumstances, I'd ask if your parents taught you how to look after yourself.'

'I don't need to look after myself,' Shadow said. 'I don't need to eat or drink, for that matter, and I can accelerate my natural processes to –'

'Enough of that.' Iain returned and pressed a water bottle into his hand. 'Look, I don't know how your abilities work. But you must need energy to manipulate spacetime, correct?'

Shadow frowned. 'Of course. What of it?'

'I know you're a military man, so how do I say this … What you're doing isn't efficient or effective. Stop wasting your energy on correcting your hydration imbalances when you can just drink a damn bottle of water instead.'

Shadow bit back a retort and snapped the lid off, breaking the threads on the bottle neck, and downed the bottle in one go. 'Are you happy now?'

'Quite. Chuffed, even.'

The door to Elijah's room flew open, and Alex leaned out. 'Director Hawthorne. We've got time for Shadow to see one more patient for blood donorship before we need to perform a bone marrow biopsy, and we've scheduled Elijah for one as well, and we need to review his treatment plan, and –'

'Breathe, Dr Alexandrite. I'm already dealing with one fainting risk, and I do not feel inclined to take on a second.'

'I do not "faint",' Shadow said.

'There's a first time for everything – including using the theory of relativity to treat acute myeloid leukemia. I'm sure people will be intrigued to hear about that at the next grand rounds conference.'

'Or at the morbidity and mortality conference,' Shadow muttered, 'Depending on how things turn out.'

'Shadow, stop it,' Alex scolded. 'I know how unwilling you are to give people false hope, but there's a time and place for pragmatism.'

'There's also a time and place to get excited, and it's after the patient has been successfully treated, not before.'

Alex considered his words for a moment. 'Hm. No.' She laughed at his aghast expression and said, 'Of all people, you have no right to complain when someone doesn't listen.' He stepped forward to argue, but she promptly shut the door in his face.

Shadow growled and flattened the bottle between his hands, tossing it into a nearby bin before following Iain down the hall. 'You'd think we'd found the cure for cancer itself, the way she's carrying on.'

'You can't give people hope without expecting them to get excited, Shadow.'

'I'm not giving people hope. I'm just giving them ideas for experimental treatments that may not even work.'

'I hate to break it to you, but that's often what hope looks like around here.'

Shadow looked away, toward the glass wall on one side of the corridor, and saw his reflection walking alongside him. '… People put their hopes in me a long time ago. Nothing good came of it.'

'Perhaps not back then. But what about now?'

'I …' Shadow faltered, and he nearly walked straight into Iain's back when the man stopped outside the door of another hospital room.

'Here we are. I'd ask if you wanted to take a break, but –'

'No.' Shadow raised one hand, resting it against the name plate on the door. Makena Williams. His fingers slipped from the nameplate to the door itself. 'That's not necessary.'

Iain watched him, and Shadow resisted the urge to glare back. '… I hope that this will be easier for you. I know you have a personal connection with the Tower family, but I don't believe you know any of our other patients.'

'It makes no difference to me whether I know them or not.' Shadow bit his tongue. They could keep doing this all day. Every time he argued back, the older man would somehow find another way to attempt to comfort him. And he didn't want comfort. He didn't.

He pushed the door open and went in, letting it fall shut behind him.

The room was lit by the light of the setting sun. His gaze flicked across the room – a pair of small, pink slippers on the floor, a heart sticker on the end of the hospital bed, and a pair of dolls lying on a nearby table.

A warm, bright voice caught his ear. 'Oh my gosh!'

He looked up.

She didn't look like Maria. If anything, she was Maria's opposite. Her hair was a soft, dark cloud, and her skin had a warm hue to it. The moment their eyes met, her face lit up, and her eyes sparkled. 'I love your red eyeliner! It's so pretty!'

Shadow blinked. He bit the inside of his mouth and walked over. He tried to fight it, but he couldn't. He sat on the edge of the bed, and a half-smile flashed across his features. '… Thanks.'

She and Maria may have lived generations apart, but their smiles were equally infectious.

The woman sitting beside the bed got up and held out a hand to Shadow. 'Hey. I'm Latifa, Makena's mother.' He cautiously took her hand, but he was completely blindsided when she crushed him in a hug instead. 'Oh, sweetheart,' she said. 'Thank you so much for helping my baby girl.'

He didn't even have time to register the depth of emotion in her voice before Makena began to protest. 'Mom! You're going to scare him off!'

'I don't think there's nothin' scaring this one off, baby.' Latifa let Shadow go and gestured towards him. 'Have you seen him?' she demanded. 'No offence, of course. You're as cute as a button, but those fangs aren't just for show, are they?'

Shadow bit the inside of his mouth again, using the fangs in question to suppress another smile. His gaze landed on the woven bracelet on Makena's wrist. It was made of red and burgundy fibers, threaded with red beads that were shaped like crescent moons.

'Want to tell me why we're both here?' Shadow asked, and he tried to keep his tone gentle.

Makena raised the wrist with the bracelet. She smiled again, but now he could see that the glassy brightness in her eyes wasn't just because of excitement. It was also because of feverishness. The beads in the bracelet looked like curved blades, and they gleamed beneath the light.

'Sickle cell disease. Do you …' Makena faltered, and her lip quivered. 'Do you think you can help me?'

'I don't know.' Shadow held out one hand, and a moment later, her fingertips grazed the palm of his hand. 'But I'll be damned if I don't try.'