A/N: ok, here's the big reveal for what's wrong with Henry. Now, some of you might think this is rather fast considering the title of the fic but Emma and Regina are soon going to be on the tail of a new mystery …

Zelena hated to admit it to herself but she did delay the moment when she finally headed to the lab to pick up Emma Swan's blood work. It wasn't that she was wasting time: her other patients needed attention too. But she definitely asked more questions than usual and tidied up her entire work station before she could no longer put off the task she had been dreading since the start of her shift.

She wasn't sure what she was most afraid of; the results returning positive and proving her theory correct, or them being negative once again and the mystery of Henry's illness becoming even more impenetrable. she was rapidly running out of theories and ideas of what to test for next. Knowing what was wrong with the small boy was better, surely … It was just the circumstances of the little family which made her stomach feel like lead as she finally entered the lab and asked for the file.

Opening the flap as soon as the document was handed to her, grey-blue eyes scanned the paper quickly, heart pounding as she took in the results.

"Shit," she murmured.

"Yeah, poor woman," a passing lab technician said. "I've never even heard of the disease you asked us to test for but my superior gave me the details. It sounds brutal. Is it treatable?"

"There's a chance of survival, yes," Zelena said thickly. "But she's not actually suffering. It's her son. Do you have Henry Swan's results here too?"

The technician turned and thumbed through the pile of files he had yet to order before finally pulling one free. Zelena had asked for the test to be run in tandem on Henry's blood work, just in case Emma tested positive herself but hadn't passed on the disease. Opening the second file, Zelena saw the result she finally realised she had most been dreading.

A distant ringing sound roused Regina from her sleep. Groaning, she burrowed her face into her soft pillow, stretching out her body before she finally raised her hand from beneath the warm covers and reached for her phone on the bedside table. Without looking at the caller ID, she answered.

"Yeah?"

"Were you asleep?" came the familiar voice.

"Of course I was, Zee. I'm on nights, remember?" Regina said, irritated at her best friend's apparent short-term memory problems and her interrupted rest.

"Right, sorry," Zelena said, not sounding in the least bit apologetic. "Um, I just wanted to give you a heads up that I've diagnosed Henry Swan. I'm just on my break and then I'm going to tell his mother."

Regina suddenly sat bolt upright, wide awake and alert. "What is it? What does he have?"

By the time Zelena had finished explaining to Regina how she had picked up on the subtle signs of the rare disease, Regina was already dressed again and heading for the door, phone tucked between her cheek and shoulder as she fumbled her feet into her shoes.

"Give me ten minutes," Regina said, grabbing her car keys and unlatching the door. "I want to be there when you tell her."

Henry pouted as the dice landed on the board and his mother moved her own counter triumphantly forwards once more, leaving his woefully behind. Well, this wasn't fair. He was sick, after all, so why wasn't she letting him win? A little irritated, he leaned forwards stiffly to roll the dice himself, beaming when his throw gained him a double six. Counting out carefully, Henry grinned as he realised all was not lost.

"Are you hungry?" Emma asked as she took her next go and looked at her thin, pale son huddled beneath the hospital blankets.

"No," Henry replied.

"But you hardly ate any lunch," Emma pointed out, indicating the almost intact lasagne that had been served by a nurse earlier. Henry had barely eaten anything since they had arrived in hospital and was definitely starting to weaken as a result.

"I didn't like it," Henry protested. "And I wasn't hungry anyway."

"Kid, you need to eat," Emma sighed, handing the dice back to her son. "The drip isn't enough to make you get better. It's good healthy food which will make you strong again."

Henry glanced around the room at the fruit and chocolates which Billy, Ruby and even Belle had brought him over the past two days. None of it really appealed to him but he knew his mother was worried so he acquiesced.

"I'll have an apple," he said finally. "But cut up into little boat wedges."

Obliging at once, Emma hopped off the bed and headed straight for a pile of succulent red apples. Ignoring the fact that she knew the fruit would have accumulate a sickening number of air miles, she took a knife from her own empty lunch plate, wiped it clean and began to cut. Upon returning to the bed a few minutes later, Emma frowned at the game board.

"Henry," she scolded. "What did I say about cheating?"

Big brown eyes looked innocently back. "I didn't cheat," he said, the corner of an apple boat entering his mouth. "You just forgot you were losing before."

Emma laughed but didn't press the matter. Anything to make her sick son happy was fine by her. So she resumed her seat on the bed and finished the game, allowing Henry his triumph despite its questionable roots. She was also pleased to see he had eaten most of the apple and was about to praise him for doing so when a knock on the door made her turn around.

"Come in," she called, slipping from the bed and straightening her sweatpants which had gone saggy at the knee after she had worn nothing else for two days straight. She forgot all about her appearance, however, when two familiar people appeared in the room.

"Doctor Lena," Henry said, waving. "And Doctor Gina."

"Hi Henry," the two women chorused, fake smiles plastered on their face fooling no one in the room but the small boy.

"You have the results?" Emma asked, face drained of colour.

"We do," Zelena said, glancing at Regina. She hadn't asked why her friend had insisted on joining her to break the news. If she was honest, she was glad of the support. "Would you like to come down to my office? I think we'd be more comfortable talking there. I'll ask Belle to come and sit with Henry."

Emma blinked, unable to reply. No, she thought. This can't be happening. They can't be about to tell her what she had been dreading. There was no way she was spending a second away from her son if …

"No," she all but whispered. "Tell me now."

Zelena and Regina exchanged looks and imperceptible nods. Each doctor took a seat but Emma remained standing, leaning heavily against Henry's bed and suddenly feeling like she would collapse were it not there to prop her up.

"Do you want us to tell Henry as well?" Zelena asked, needing to know how to phrase the news.

"The basics, if that's appropriate," Emma nodded, her fingers drifting towards Henry's hand and clasping it. The small boy didn't seem to mind. He was watching both the doctors curiously, trying to understand what was going on.

"Do you know what's wrong with me?" he asked at last, breaking the heavy silence.

"We do," Zelena said.

"Am I going to get better?" Henry said simply.

There was a tense pause. "Hopefully," Zelena said at last. "Henry, you have a something called X-linked Lymphoproliferative Disease and it means your body finds it difficult to make you better if you get ill."

"X-Linked Lympho-what?" Emma repeated. "What is that? I've never heard of it."

"X-linked Lymphoproliferative. It's a very rare genetic disease," Zelena explained. "One of the earliest symptoms however is an extreme case of glandular fever and combining that with Henry's peculiar blood work and his stiffness symptoms made me suspicion."

"So what is it?" Emma asked.

"Henry has a weakened immune system," Zelena repeated. "His antibodies are very low and his body is going to struggle to defeat illnesses such as glandular fever."

Emma slumped back against the bed. "So … what can we do? I mean, what does that mean?"

"Well," Regina began, speaking for the first time, "you're lucky Doctor West caught this so early. With a diagnosis in good time and before the development of lymphoma, Henry can -."

"Lymphoma?" Emma interrupted. "Cancer?"

"I have cancer?" Henry piped up, recognising the word from television as something bad which he didn't quite understand.

"No, you don't," Zelena said at once. "And hopefully we're going to make you all better before that ever happens."

"Yes," Regina said, continuing what she had been saying. "In early diagnosis cases such as these, Henry's chances of making a full recovery are much higher, provided we move quickly."

"What chances?" Emma asked. "What are the statistics?"

"The current survival rate is thirty per cent," Zelena admitted, glancing towards Henry to see if he had understood. He wasn't even listening, too busy making a pair of apple boats race around the plate.

"Thirty," Emma repeated, the number caught in her throat.

Thirty per cent survival. Which meant seventy per cent of people diagnosed … she couldn't allow her mind to head down that road just yet. Instead, she swallowed thickly and looked between Regina and Zelena.

"What now?" she asked. "How do we make him better?"

"A bone marrow transplant can offer a cure for early diagnosis cases and this is certainly one of those. You're lucky you brought Henry in so quickly after he went down with glandular fever. He's still strong enough to be eligible for a transplant. But there is one problem which we're going to need to overcome first."

"Problem?" Emma asked, instinctively looking at Regina for the answer even though it was Zelena, Henry's official doctor, who had been talking before.

Regina hesitated before answering. She didn't want to step on Zelena's toes professionally but the pleading look on Emma's face compelled her to break the news.

"Since you passed on the defective chromosome to Henry in the first place, you're going to be ineligible as a donor," she said gently. "And because of your … family situation, there's no obvious second choice which means we're going to have to put Henry on a list and wait for a match."

Emma's eyes burned as she realised what Regina was telling her. Not only was she the cause of her son's sickness in the first place but the fact that she had herself been too unlovable as a baby and then slept casually around as a young adult meant Henry had no other familial match upon whom he might be able to depend for a transplant. Because of her, Henry's chances of survival just went way down.

Without speaking, Emma ran from the room, hand covering her mouth to stop the sob escaping before she had reached the corridor. Regina and Zelena watched her leave before turning back to the confused boy on the bed.

"Where did Mum go?" he asked, frowning at the closed door.

"She just needs some time to think," Regina said.

"About me being sick?"

"Yes," Zelena replied. "But she'll be back really soon and then we can start working out how to make you better. Have you eaten much today?"

Henry shrugged and nodded towards the left-over lasagne. "I usually like lasagne but that stuff was gross," he announced. "The apple was ok, though. But I'm not really hungry much at the moment."

"It's important you eat," Zelena said. "The stronger you are, the quicker we'll be able to get you out of here and back home."

"Can I leave today?" Henry asked, face lighting up at the prospect.

"No," Zelena said sadly. "There are some things us doctors will need to do with you first. Would you like me to talk to you about what's going to happen?"

Although Zelena usually preferred to speak to children with their parents present, Henry was a bright young boy and Emma herself had consented to the pair of them being told about his illness together. She figured she would be able to explain what was wrong with him and the treatment whilst Regina was tracking down Emma and talking to her. Clearly the two of them had a connection and it seemed only logical to send her friend after the devastated mother.

So as Zelena pulled her chair up to the side of Henry's bed and began to explain in simple language what the disease meant and what their plan for the transplant was, Regina slipped from the room in search of a certain blonde.

The wall was cool against Emma's back but apart from that she felt numb. Her mind, so overwhelmed with the deluge of information it had just received, was unable to register anything more. It wasn't sinking in. She wasn't able to comprehend what Doctor West and Regina had told her. It couldn't be true, could it? Not Henry. Not her kind, sweet, perfect little boy who had never been ill in his life. And even if it was true, it couldn't be because of her, could it? Emma bit the inside of her cheek, forcing away a wave of her own guilt. This was not about her. It was about Henry. Her only son.

There was a creek as the door to the bathroom swung open. Emma gulped down lungfuls of air, trying to stop her sobbing. She heard someone walk into the cubicle next to hers, go to the toilet, and leave. Once she was alone again, fresh tears flowed down her cheeks, soaking into her knees as she buried her face against her legs.

Not Henry, not Henry, not Henry.

Their life had been pretty great. Not perfect, but good. After Lily left, Emma had picked up the pieces as best she could and focused all her energy on her son and giving him the stability and love he deserved. She was determined he was never going to get attached to another parent-figure upon whom she couldn't rely. That was why she hadn't dated even though it had been over two years since Lily left. He didn't deserve to be walked out on ever again. And now … well, now it might be Henry who was leaving Emma.

As the realisation of what they were about to face washed over her, Emma's cries bounced off the bathroom tiles and she collapsed fully onto the floor, curled up a ball and sobbing uncontrollably. She didn't even hear the door open nor the footsteps approaching the far side of the cubicle door before a gentle knock on the wood was followed by her name.

"Emma?"

She would know that husky voice anywhere. She couldn't face Regina now. Not like this. She couldn't face a doctor who knew she was the reason her son was ill. What would the brunette think of her? This mother who had made her son so sick and couldn't even provide him with a family who could help. Emma was a disgrace, an unfit mother.

"Emma," Regina repeated. "Please let me in."

"No," came the choked response.

Regina sighed and leaned against the door, relieved at least that she had correctly identified the woman whom she had heard crying from the corridor as she walked past during her search.

"Emma, we can talk about this. I can help, but please come out so we can go somewhere private and talk face to face."

There was no response, just more crying. Regina slid down the wall and sat with her back against it, waiting. Eventually, the sobs began to quieten and a rustling implied Emma was moving. After another few minutes, the latch slid back and the door slowly swung inwards, revealing Emma sat in the same position as Regina, eyes red and face blotchy.

"Come on," Regina said, getting to her feet and helping Emma to hers. "Let's go and find a room so we can talk."

Without a word, Emma allowed herself to be led from the bathroom and down the corridor until Regina located a vacant family room and steered the silent woman inside. Emma sank into a soft chair, staring straight ahead. Assuring Emma she's be right back, Regina rushed to the canteen to buy two coffees before returning. In the five minutes she had been gone, Emma hadn't moved. Regina doubted she had even blinked. With a coffee on the table in front of each of them, Regina sat opposite the stupefied blonde and, eventually, their eyes met.

"Hey," Regina said gently. "We're going to get through this, Emma."

The blonde didn't reply. She just waited for Regina to say more. So she did.

"Henry's early diagnosis has given us a great chance. We have a few months in which to find him a donor and we will start doing so immediately. The problem is, however, that in the absence of a familial match, he is going to have to go on the transplant list and wait for a random match. Henry also has a blood type which can only receive transplants from a donor of the same group, O negative. This is going to make it harder to find a donor but we can't give up hope already, Emma. Now we know what's wrong, we are going to do everything we can to make Henry better."

Still there was no response. Regina reached forwards and took one of Emma's hands. The skin was cold and clammy.

"Emma, do you have any questions?"

There was a long silence but Regina could tell there was something the blonde wanted to say so she waited patiently.

"Why?"

The single word was barely a whisper and Regina frowned in confusion. "Why what?"

"Why him?" Emma suddenly spat, pulling her hand from Regina's and standing up. "Why Henry? Why my son? Why did it have to be him?"

"That's not a question you need to ask right now," Regina said, watching the young mother carefully.

"Because the answer is me, you mean?" Emma all but shouted. "I'm the reason he's ill, right? I'm the fuck-up who passed on some faulty gene to my son and now he's sick. If it wasn't for me, if I hadn't been such a slut that night I would never have killed my son."

"Hey," Regina said, jumping to her feet. "Don't talk like that. He's not dead, Emma, and regardless of what happened that night, it gave you Henry, right? He's a gift and he's lucky to have you for his mother. With you by his side, he can fight this."

"How?" Emma yelled. "I can't! I'm toxic to him. I made him ill. And his father, fuck knows where he is. I don't even know his last name! Just that he's a good shag and didn't have the manners to say goodbye the morning after." Regina blushed but Emma didn't notice. She just kept going, anger seething from every pore. "And as for his grandparents, I was such a disappointment to them that they gave me up when I was a few hours old. Every person who could have helped I drove away. I'm the only one he has and I'm the reason he's dying in the first place."

"He's not dying, Emma," Regina said, crossing the room and gripping Emma firmly by the upper arms, ignoring the feel of the toned muscles beneath her fingers. "You have to stay positive."

"Thirty per cent survival," Emma repeated. "Thirty fucking per cent, Regina. And with no family and an incompatible blood group that drops to what, five?"

"I don't know the exact figure," Regina admitted. "But we can't give up hope. We haven't even begun to look for a match."

"So we're just going to sit around and hope some good samaritan who just so happens to be a match for Henry donates their bone marrow? How am I supposed to be hopeful about something so unlikely?"

"Because hope is all we have," Regina said shaking Emma lightly. "We have to hope, Emma. We have to believe that Henry is going to get through this."

"And what if he doesn't?" Emma asked, tears pooling in her eyes as the wave of anger receded as fast as it had come replaced by overwhelming grief and despair. "What if we don't get a match? What if he …"

Regina didn't know what to say in answer to the uncompleted sentence so she did the only thing she hoped would make Emma feel just a little bit better. She pulled the distraught mother into her arms and hugged her as tightly as she could, the blonde's tearful face buried against her neck. She felt her own eyes burn but bit back the tears. Emma needed her to be strong right now. She needed support. She needed Regina to be her doctor, nothing more, she reminded herself as she felt Emma's quavering body pressed tightly against her own.