Afterwards, he remembered his hospitalization only in scattered moments. Time seemed to hold no meaning; he had no notion of how much of it might have passed. He might have been in that sealed-off room for only seconds or for months, for all he knew. His life shrank to the simple physiology of respiration. Breathe in, breathe out. That was all he knew. The rest of his body was useless; it was all he could do to keep breathing.

He was vaguely aware of hands – moving his body, touching his hands, checking his vital signs – always there. Faces hovered – masked, their voices muffled. Once – more than once – it was Nikki hovering over him – no, that wasn't right… She wasn't Nikki, but she had her eyes – brown, gentle, all the compassion in the world focused right on him. Her voice was different, though – lower, but insistent, constantly reminding him to focus on his breathing. He knew she didn't want to have to ventilate him.

"Jack? Jack?"

Her voice came again… but no, this time it was Nikki's voice. His eyes flickered open, sought desperately, and found them. Two figures – the two most important people in the world. Faint behind the plastic walls, but clear enough. Her voice… his voice…. He heard the quiver in his father's voice, the fear…

"I… love… you."

The words were for both of them, neither more than the other. In that moment, it didn't matter that one was his old dad, with whom he had a complicated relationship, and the other was the most beautiful woman he'd ever seen – the woman that he dreamed, every night, of kissing, of touching, of holding in his arms all night. Both were his world. Both were all that mattered.

He watched as her head fell upon his shoulders – watched them desperately until both faded from sight…

There were other moments, though that was the most vivid, and the one that always stayed with him afterwards. It was a moment of pure clarity in a world gone mad – the moment he realised that Nikki would always be the one and only, that there would never – could never – be anyone else for him. That he'd die a single man if he couldn't have her.

He remembered Clarissa standing at that window – her words to him. "I would have told you first, but I knew you could talk me out of it." He remembered the tears she dashed away before anyone could see them. Something else that didn't quite make sense to his wandering mind: "I can't lose you too." He remembered Max once – his hand on the glass partition. "Come on, Jack, you've got to make it. Clarissa will never forgive you – you do know that?"

And his father, always his father. "Don't you go focusing on me now, son. Your old da's OK. You just focus on getting better, you hear?" And another time, dearer than dear. "You're my boy… You remember that now. You've always been my boy."

He could never remember Thomas. That hurt, afterwards. He knew Thomas had been there at the beginning. He had a vague memory of trying to tell somebody something, but he hadn't been quite sure if that was Thomas or someone else – it was Nikki who confirmed it later. In the early days of his rehabilitation, he found himself relying heavily on Nikki and Clarissa to fill in the gaps where they could.

He wanted to remember Thomas. He wanted to remember the clever, quirky, sometimes fussy, quietly amusing, unassuming, kind man who had sacrificed his own life to save Jack's. The man who'd had been forced to leave his teenage daughter without a father. The man who'd cared enough about him – Jack - to take the ultimate risk. He wanted to go back years – to the moment they had met – and learn everything there was to know about Thomas. What motivated him, what he loved and hated, what had made him become a pathologist, what his hopes for the future were. If only he could go back, if only he could tell Thomas how much he respected and liked him. How much he – yes, in the end – loved him. How much Thomas could have been the brother that Jack had always wanted.

Most of all, he wanted to know why. Why Thomas, and not him…and, God forbid, why not Nikki? Why hadn't he been able to tell someone about the crumpled note in his pocket – that evil little document? If only Thomas had found it, if only they'd been able to decipher its meaning without Thomas having to test the vial…

He would never forget the day Nikki told him Thomas was dead – the way she'd tried to stay outwardly calm to not disturb him, but then her face had crumpled up and she'd sobbed - harsh choking agonized gasps that told him more than words ever could. He'd wanted so much to hold her in his arms at that moment, but he could do no more than put his heavy aching hands over hers in mute comfort as the tears ran down his own face.

He had plenty of time to brood over Thomas' death. His recovery was painfully slow. The doctors were hopeful that his neurological system would recover once they had the correct treatment, although they didn't have enough evidence to rule out long-term nerve damage – there were too few tabun survival case studies for them to draw on. Being on a ventilator had done him no favours either; he'd required emergency dialysis and although his kidneys were functioning properly again, he'd need regular screening for the rest of his life. His muscles had atrophied. He needed help to complete the most basic and intimate activities; it was humiliating to be so reliant on the nurses at the rehabilitation unit they transferred him to. Even when the physiotherapists had him up and walking on a treadmill, it wouldn't take much to leave him breathless and shaky.

Nikki, Clarissa, and Max supported him as much as they could. His father's operation was reorganized and went ahead – it was as routine as Thomas had said it would be, but Max kindly stayed at Connor's flat for the first couple of days, sleeping on the sofa and making sure Connor was comfortable and mobile. Connor rallied far more quickly than Jack could have anticipated. The fear he must have felt about losing his son appeared to have galvanized him to sort out his own life. He was soon as mobile as he had been before getting ill and was Jack's most frequent visitor.

Clarissa had agreed to stay on at the Lyell as long as she was needed. She and Max had had no firm plans anyway, and they were more than happy to put them on hold. That was a massive relief to Jack, who couldn't bear to think of Nikki having to carry on alone in the Lyell. It was a while before they could even get into the place. All the laboratory equipment, their scrubs, and any spare clothing they kept in the vicinity had to be destroyed and the entire building deep cleaned. The MOD had done a thorough sweep of the office as well, looking for evidence, and Nikki found most of their personal items had been ransacked and left in an unholy mess. The worst job had been identifying Thomas' things and boxing them up for Cassie. Clarissa told him much later about the day she'd found Nikki sitting on the floor and sobbing as she held the broken frames containing Thomas' certificates, the glass shattered, and the papers ripped.

Jack could only guess at most of what was happening at the Lyell, but he could see Nikki's red-rimmed eyes and strained face whenever she visited him. She'd lost weight again; in fact, she reminded him of the weeks following Mexico. He was afraid that she might collapse under the strain and cursed his stupid, slow body for preventing him from being able to support her. He tried to improve her mood whenever he had an opportunity – making light of his own struggles and doing his best to remind her that she was not alone. She was his first focus whenever Clarissa or Max visited – he always wanted to know how they thought she was doing and nagged them into cooking for her. He found he had to restrain himself from texting to remind her to eat or sleep.

He even recruited his father to the task – asking him to ring Nikki from time to time to try to distract her from her worries. Connor did more than that; he invited her out to lunch. Jack would never know how his father had charmed her into accepting the invitation; perhaps it had simply been in Nikki's compassionate nature to accompany a lonely old man to lunch. Maybe it was the shared memory of that day in the hospital when they'd stood at his window and supported one another…but, whatever it was, something clicked between the two of them from that time on.

It became obvious that they were collaborating in his recovery, taking turns to visit, and even conspiring to smuggle in little treats where possible. Nikki's mood began to improve; she regained some weight and had more colour in her cheeks. The first day he was allowed out into the grounds, it was Nikki who pushed his wheelchair while Connor walked alongside. He remembered very clearly the sun warming his face and Nikki's husky laughter as his father joked about Jack's childhood. It felt like a breakthrough.

Nikki became more tactile – far more openly affectionate than she had ever been. She'd occasionally greeted him with a kiss on the cheek in the past, but now did so each time she walked through the door of his private hospital room. She'd touch his arms, hands, shoulders frequently; she'd ruffle his hair in casual affection before smoothing it down and sometimes planting a kiss on his head. During most visits, sitting in the chair wasn't good enough – she'd wriggle onto the bed next to him and lean her cheek against his shoulder.

While these affectionate touches warmed him, he wasn't entirely sure of their meaning. Nikki wasn't flirting with him – at least, he didn't think so. It was more as if she needed a constant reminder that he was still there, as if the sight and sound of him weren't enough to reassure her. It was clear that she was still trying to process the trauma in her own way – not just of witnessing Thomas' death, but of seeing him dying and not being able to touch him or provide any comfort. Well, he knew how that felt…

She never mentioned Matt, and Jack wasn't about to bring the subject up. He did notice that she didn't go away at all during the two and a half months that he spent at the rehabilitation unit. Even for some time after he'd been discharged home, she was in and out of his flat most days. While he appreciated the concern, he needed to feel normal again. The physiotherapists and occupational therapists wanted him to try to do as much for himself as possible. It amused him to see Nikki hovering, almost quivering with her desire to help, as he completed the simplest of tasks, such as making a cup of tea.

Slowly, slowly, he recovered. Indeed, slow was the word - he discovered a new understanding of the physical limitations imposed upon Clarissa and his father. It shocked him how long it took to walk down the street to the corner shop and how tired such an excursion could render him. Running was out of the question, but he made his way back to the gym as soon as he was able, where Andy was touchingly pleased to see him and happy to help him work out a programme. Gradually, he grew fitter and less dependent on his friends.

Then, a few weeks after his return home, Nikki flew out to Washington for a week. And everything (or almost everything) seemed to have returned to normal.

Returning to the Lyell was odd.

He'd been absent for nearly five months. He stood in the office and looked around him, as if trying to find something familiar.

It wasn't that Nikki had redecorated or anything, but the space seemed empty. Sterile. Frighteningly neat, for a start. The mess had often driven Thomas mad (oh, God, Thomas…), but it had worked for Jack, Nikki, and Clarissa – a sort-of controlled chaos. They were used to manoeuvring around teetering piles of unprocessed files, half-drunk mugs of cold coffee, discarded items of clothing - the general accumulated detritus of three individuals who probably spent more time at work than was entirely healthy.

Now his desk was practically empty but for the computer. It gleamed with polish. There was a small box on it containing his belongings – those that Nikki had managed to rescue from the MOD. As he looked around, he could see more boxes in various corners. It was as if Nikki hadn't had the time or the heart to put everything back. It seemed that she and Clarissa had simply retrieved whatever they needed for their current purposes, abandoning the rest.

The Lyell had only reopened completely a couple of months' ago. Initially, they'd had to wait until the centre had been passed as safe to enter; even when they could re-enter it, the building was hardly habitable, let alone able to operate as a pathology lab. Nikki had had to reorder all the equipment and sort out the chaos left behind. The staff had been put on furlough, but many had since found employment elsewhere, so she'd had to interview new laboratory staff. She'd then had to rebuild the Lyell's reputation by encouraging the Met's detective inspectors to use them. In that, she was surprisingly lucky – despite her past difficulties with some Met officers, many were sympathetic. She'd started off slowly with more straightforward cases, such as traffic accidents, where the exact sequence of events was in dispute. The kind of cases where Clarissa's skills with CCTV footage and events reconstruction were undisputedly the best in the business.

Jack walked into Thomas' office. It was a forlorn space, empty of all but the furniture. Clearly nobody had moved in yet. He didn't actually know who would. He assumed Nikki had been approached once more about potentially taking over. She hadn't been keen before, and he couldn't imagine she would be now.

Part of him hoped she would take over the Lyell, on the grounds that it would prove she was committed to staying; another part of him desperately hoped that she wouldn't, for the very simple reason that it would make her his boss.

He had a very specific reason not to want that to happen. Since his illness, he'd noticed a change in Nikki in relation to Matt. Her visits were far less frequent – she'd only been over there twice in the last five months, and he hadn't visited at all. Nikki hardly ever mentioned him. Jack thought he'd know if they'd actually split up – he was sure Nikki would have told him – but he had at least some hope now that they were no longer a serious item. And one thing was for sure – if Nikki did split up with Matt, Jack would not make the same mistake again. This time, he would make his move – he wanted her, and he would make sure she knew it. No messing around, no casual flirting, no tentative suggestions to see if they got a response. He'd be honest about it - he'd ask her out for dinner, he'd damn well tell her how he felt. It'd be a hell of a lot easier to do that if she wasn't his boss.

"How're you doing there, Jack?"

It was Clarissa. She'd come in one last time to gather up her belongings. The long put-off Caribbean cruise was finally booked; they'd be off before Christmas. She wheeled herself into Thomas' office.

"Feels odd, doesn't it?"

That gave him a jolt. "He said exactly the same thing to me – when you went away. He thought you might not come back."

She sighed. "He was a very clever man – Professor Thomas Chamberlain. I miss him."

"I wish I'd got to know him better," Jack admitted, looking at the bare wall where Thomas' many qualifications had been so proudly displayed. "There was so much more to him than met the eye."

"I think Nikki saw it," she said, quietly. "She loved him - perhaps not as much as Leo, but in a different way."

He nodded. "He really was everyone's big brother, wasn't he? I just didn't see it soon enough..." He shivered slightly and turned to leave the office; the silence was starting to feel oppressive. "I also remember him saying that he didn't know what I'd do without you and Nikki."

She followed him out. By her desk, she stopped and stared at it, as if trying to memorize the sight before she started to clear her possessions away.

He sat at his own desk and watched her across it. "I know I don't know what I'll do without you. I know you're doing what's right for you, but…it breaks my heart to know that this'll be the last time I'll be able to look up and see you there."

She looked up at him, tears sparkling in her eyes. Clarissa-like, she dashed them away impatiently. "I'll always have your back. You know that. Doesn't matter where I am, doesn't matter when it is. You can ring me any time."

He lifted his hand, extended it for the familiar fist bump. "Any time?" he teased. "Not sure Max'll be on board for that."

She grinned. "He'll have to be. Anyway, Hodgson, you're acting as if we'll never see each other again. Don't forget Sunday lunch, and don't forget to pick Nikki up on the way - not that you're likely to," she added, with the familiarly suggestive arch of her eyebrow.

He shook his head in mock disgust. "Same old inuendoes. Some things don't change."

"They'd better." Her voice was surprisingly brusque, and he looked at her in surprise. "You nearly died, Jack. You need to sort your life out, once and for all. I won't be here to keep an eye on you, so this is my last chance. Let's not beat around the bush here – you are in love with Nikki."

He nodded, adopting her serious expression. "Yes, absolutely right. I am in love with her – have been for years, probably."

"And you're going to do something about it, aren't you?"

"Yes… I need to wait until the time is right."

She sighed, shaking her head irritably. "Jack Hodgson, you will be the death of me!"

"No, wait," he raised a hand to stop her. "I need to find out what's happening with Matt first. But I will. I promise you. I'm not going to mess it up this time."

She sighed again, seeming to accept this, and gazed at her desk. "Well…this won't clear itself."

He stood up. "Give you a hand?"

"Two if you can spare them." She began to sort through some paper files while he fetched an empty box. "These are just for inputting and filing away. You can give them to Lynne – she's very efficient. The open cases are on your desk, and I've emailed you the notes… Think you're ready to get back to it?"

"You betcha." He felt almost as healthy as he used to. Boxing was definitely out for now, and he might never again be fit enough to compete. He'd started running again, though, and delighted in the feel of his muscles responding smoothly to his brain's instructions. His experiences had left him with a newfound empathy for those with neurological disorders. His mind felt fresh and keen; he was ready to get stuck into a case.

"I was just thinking…"

"Steady there," she muttered, as she opened her desk drawer.

He grinned. "Are you free tonight?"

She gave him a suspicious look. "I…can be. Why?"

"I'm thinking dinner…"

She gave him an arch look. "Michelin stars? You're on, Jack Hodgson."