Chapter ten takes place at Ruth Tyler's house as Sam and Gene compare their childhood memories of the 1970s and 1980s, they speak to a former member of Greater Manchester Police CID for information.

Sam remembers this sofa; the spring that never fails to dig into the flesh at the top of his thigh. The chequered throw that covers wilting pink flowers and Edwardian curves. Sitting on this sofa, after all this time - it's strange. The same cognitive dissonance that came with having to learn to walk again. He never stopped walking. He's used to browns and oranges, the smell of leather and stale cigarettes. This room is too clean and orderly, but it's familiar, like looking through the bottom of a bottle and seeing the world all warped and smeared. That dark shape in the corner is a fern, you've touched that fern, you bought that fern, but when you look at it through moulded glass - it could be anything.

It's the details he never expected to cut close to the bone. His mother's perfume. The coffee-ring on the table. They're all right and still wrong. Sam shifts uncomfortably and tugs on the cuff of his jacket, because it itches in ways the other never did.

"Do you still have those boxes in the cupboard under the stairs?" he asks his mum when she settles next to him and pours the tea.

Ruth shrugs one shoulder. "Why wouldn't I? What did you want them for?"

"I wanted - to look." To savour. To sense. To find anything that might make him feel better.

"Did you want my help? Was there something specific?"

"No, I'll be okay. Can I do it now?"

Ruth stares uncomfortably closely. Sam drags a finger around the rim of his cup. He remembers this tea set. It was a forty-fifth birthday present.

"They're covered in dust."

"I like dust. It gives a sense of time and place."

Ruth frowns. Sam ignores it. He stands, shrugging off his suit jacket and draping it over the sofa. He rolls up his shirt sleeves and glances towards the sliver of cupboard he can see through the doorframe. Takes a hesitant step and then strides towards his goal.

He drags the boxes into the kitchen and settles on the floor with them. They're heavy and his arms are still weaker than they once were, so he doesn't even bother trying to lift them onto the table. He hears Ruth stepping out of the lounge and has a horrified moment where he thinks she's going to come and join him, pauses waiting, but she calls that she's going to go buy some more milk, asking if he wants anything. He says no, but he doesn't mean it; he just doesn't want anything she can offer.

The first box he opens brings back memories of going down to the record shop with Gene and listening to as many EPs as he could before the owner would tell him to sod off, before he finally saved enough money from mowing next door's garden to actually buy a 7" single to take home and play. Gary Numan, thick eyeliner and suit; incongruous like he feels now. An old record at the time of purchase, but only by a few years. He almost had enough for another, but couldn't decide between Dylan and the Stones. Later, he'd wished he'd gone for Bowie, but hindsight was always clearer.

There's his school jumper; grey with a hole near the collar. It's tiny, thin and worn. It had to last four years and he got into scrapes and scraps more than any other kid his size, he'd wager. Never could keep his mouth shut even then. He's not sure why it's in here. He'd have chucked it years ago. Beneath his jumper there are copies of school photos. The others are proudly displayed around the house, but his mum always insisted he get four, to give to his Aunties, and somehow they were always left with one to spare. He looks at the bowl cut, the side parting, the Elvis impersonation and the attempt at a mullet. Every year a new style. And that's him, apparently. Doesn't seem like it. He could be looking at any serious child, guarded eyes and straight line where a smile should be.

This is the wrong box. This is a box for Gene's years in secondary school; working hard, fighting harder, being confused sexually and emotionally, and just confused in general. These are the years he became obsessed with The Professionals and The Sweeney, and tried to stop thinking about his Dad, proving he was the man of the household. These are the years he lost his virginity in the back of a Ford Granada to a girl called Jenny because he wasn't brave enough to make a move on her brother Brian, and loved it all the same, cherishing the St Christopher's Medal she gave Gene, wearing it still.

Sam brushes his fingers lightly over the objects and places them carefully back. He works at the flaps of the other box, but it's sealed with duct tape and he needs a stanley knife to attain access to its contents. He slices the pad of his index finger open and sucks at the wound out of instinct, but doesn't feel the sharp sting he'd expected.

Digging through, he sees that this is what he was searching for. The right decade, the items that evoke sense memory more recent than nostalgia should allow. The first thing to arrest his attention is a small metal box his Uncle Martin gave him after he married Auntie Heather. He used to keep his football cards in it. Sam opens the box reflexively, and almost smiles when Bobby Charlton's determined face stares up at him. He closes the lid with a snap and continues dragging things out of the box, placing them on the cool tiles of the kitchen floor. Shifting a battered looking address book, he sees a dog-eared photograph of him wearing a policeman's hat. He gazes at it, uncertain. He took it, this photo. It was his. In his flat. It shouldn't be here, lying underneath a book in a box his mother has kept for years. He picks it up, smoothing his index finger over his face, and flips the photo over. Written in the corner are a few scrawled words. He knows this writing. It's not his mother's, and it's not his.

I thought you'd go looking. Keep at it.

"I never understood that, why he wrote those words," Ruth says. Sam starts. He hadn't heard the door open, hadn't sensed she was there. He looks up at her leaning against the doorjamb, tucking a strand of grey hair behind an ear.

"Who?"

Ruth's eyes cloud and she gives him her 'never bother' smile. "I expect you're feeling tired and hungry?"

Sam struggles to stand, feeling ferocious in his curiosity, his voice hard-edged and gravelled. "Who, Mum?"

"There was a police officer I knew once. Well, two of them, really. But this one, the one who wrote that line. He was a DCI - Hunt. Nasty bloke, like so many of them were back then. They thought they ruled the world and could treat people like muck."

Sam swallows. "Gene isn't like that." He gives a rueful huff of breath. "Never, I known him since we were kids."

Ruth doesn't appear to hear him, Sam can't tell if that's deliberate. "The other officer, he'd taken this picture, apparently, though I can't see why. He always was so strange."

"Did he remind you of anyone?"

"Hunt? He's your lovely mate, but his father was a right nasty piece of work as a copper back then."

Sam stops himself from shouting and manages a harsh whisper instead. "Tyler."

Ruth looks away and sounds distant and light. "Not at the time, no."

Keep at it, the photograph says. Sam tries, begs his mother for answers, but she's not forthcoming. She gets wild-eyed and scared, and suggests calling Doctor Caulfield, which results in Sam asking no more questions and pretending he's simply feeling unwell. Psychiatry has no place in his 'support network'. He'll participate in various evaluations because he's told to, but that's in a series of recordings. No need to look into kind eyes and placating gestures, or experts who talk about shock. Sam repacks the boxes and dumps them back in the cupboard, tucking the photograph into his pocket. He calls a taxi and kisses Ruth on the cheek when it arrives with the blare of a horn.

Sam stares at glass buildings during the trip to the mill. These are the products of rejuvenation, millions of pounds poured into making Manchester brighter. But it's lost character somewhere along the way; so it may be better looking, perhaps, but it's not the place Sam thinks of as home. He hadn't noticed, before. The change, though sudden in some respects, had been slow in others, and when things progress around you, it's hard to remember where they start.

The bricks are cool against Sam's palms and cheek. The daily ritual. He breathes in and imagines he can feel the industry alive again. The kids who live in one of the flats around the corner have taken to shouting obscenities at him - lie in wait just for the purpose, but Sam doesn't care, because he needs this. He climbs the stairs to his flat, fiddling with the key, stripping out of his suit, placing the photograph face down on his glass-topped table. He showers to erase a day of meetings and discussion; some more useful than others. He uses soap, but never gets clean.

When he's sitting with a towel around his shoulders and a bottle of scotch by his hand, he studies Gene's father's writing once more. It's neater than his own, not as masculine as he would have thought. The letters curl and loop together, as if it's one continuous line. And he wonders; what did Gene's father hope to achieve writing him this message? How did Gene's old man know to do so? What happened after the shots were fired?

Sam has nightmares, mostly because he refuses to take his sleeping pills. He sees the betrayal in his right hand man Gene's eyes, hears Annie's shouting, watches time and again as Chris and Dean fall at a case in London. And if they could see what had become of their 1970s counterparts, he couldn't have this note.

Sam drinks until he's too sick to swallow, insistent pounding behind his eyes, his ears ringing.

It's only because of Maya that Sam still has a job, but he never sees her anymore. She moved on. She had to, he knows this. When he called her to say thanks for her recommendation, Maya sounded strangled and tense. She'd been crying, but didn't want him to know. He could say the same, but for different reasons. Sam accepted Maya leaving him months before, so he isn't bitter, but he misses her. She would listen to him without judgement; yet he can't leave her with this burden, so he doesn't try to contact Maya more than he has to through official channels.

He doesn't pine for her in the way he expected to. He doesn't long for her touch, or the heat of her body against his in the morning. He doesn't daydream about her long eyelashes and wicked smile. It surprises him, at first. He thinks he should want to be with her on a visceral level, that he should crave sensation. He does, but not with Maya. The conversations he replays in his mind are more grating and clipped. They're deep, in more ways than one; things that were frequently said, some that never were. Sometimes, he touches a thumb to his jaw and remembers a punch with fondness. Other times he buys two bacon butties, setting one on a plate in front of him as he eats the other with relish. The kids around the corner might be right when they call him 'fucking whacked in the head', but everyone has their little vices.

It's Maya who helps Sam in his quest to 'keep looking'. She requests files he's not allowed to ask for now that he's been relegated to a sit and listen position, and has them delivered to his desk in boxes plastered with a yellow post-it bearing the words 'good luck'. Sam suspects Maya doesn't want to know what she's sending the well wishes for. He trawls through papers and folders after work for hours, finally alighting upon reports that detail Leslie Johns shooting Gene's team down. There is no mention of a Sam Tyler, or anyone of his description in the 1970s Greater Manchester Police archive. No M.A.R.S. No conspiracy. There is a grainy photograph of Gene, Annie, Chris, Sam and Dean taken in the late 1990s; Gene bullet torn and resting on a crutch, glaring into the camera with a fierce set of his jaw and flint eyes, everyone else looking vaguely shocked and in various states of pain. They were saved, according to the report, through the foresight of other officers from A-Division. They were saved.

After so many nightmares of death and destruction, his chest tightens with relief at this, the simple acknowledgement that not only did they exist, but likely continue to do so.

Sam wipes away the tears that fall thick and fast down his cheeks, pressing fingers to the bridge of his nose and shuddering out breath. Tears of joy, or tears of sorrow and regret, or a bit of both, intermingling. He takes his time and doesn't continue rifling for more until the sun is a pale orange in the sky and his back hurts from constantly leaning forward. Other people he's forced to work on policy-making with will be here soon, and he can't be seen leaving with entire boxes of classified information, so Sam works methodically, but finds nothing further. He places his one piece of evidence in his inner jacket pocket, close to his heart.

It's only after he's been to the vending machine to get a coffee that Sam thinks to take the photo out and flip it over. There, along the top, in that same, flowing style, are three words that make him abruptly stop in his tracks.

Hunt for me.

He'd grimace at the pun if his pulse wasn't racing. There will be more favours to cash in, but he can't not know. Whatever instinct lead him on this path, he has to see it to its end, even if he doesn't like the results. Even if Gene has sent him on this chase only so that he can exact dark and brutal revenge. But there would be no communication if this were the case. Gene must know something he doesn't.

Sam calls in sick from the downstairs toilets. Evans, Glen's replacement, says he thought he saw him in the corridor. Sam jokes that it must have been a phantom. The smile in his voice doesn't reach his eyes. That day, he goes home and tries his own independent search, but as he'd predicted, 'Stephen Hunt' comes up with DNA websites and he's blocked from any useful databases. He tries everyone he can think of in CID to little avail, but succeeds with an article about Phyllis.

Phyllis Dobbs, 77, seen collecting the Intergenerational Darts Trophy on behalf of the team from the Alexandra Lodge Care Centre
A retired officer of the Greater Manchester Police, Dobbs is said to be formidable opposition.

"That sounds about right," Sam mutters to himself. He's been doing that a lot lately. Phyllis of the photograph looks like someone he wouldn't want to cross; the sort of grandmother that would feed you deliberately disgusting sour sweets and expect you to fall over in thanks. Once again, Sam finds this fitting. He finishes reading the article and jots down the address for the centre. It's an expensive looking building on Wilbraham Road. He'd never really thought about where Phyllis would want to spend her time outside of work, having half-formed notions she lived in the station behind the front desk.

He attempts sleep before the journey. He looks like shit and thinks he should try to look presentable. But he doesn't manage anything resembling relaxation, his muscles and nerves wound tight.

Another taxi, because he still can't bring himself to drive, and Sam is gazing up at red brick and wondering how fast he could run away. Instead he inquires at the front desk as to where Phyllis might be; stating he's an old family friend. It's a version of the truth, he supposes, though not an exact one.

"He said you'd come. I never believed him," Phyllis says without preamble. She's sitting by the window, a crossword open on her lap.

"Hi Phyllis." Sam sits opposite Phyllis, perching on the end of her bed. She tuts at him crinkling the quilt.

"Well, until one day I saw you on the telly banging on about a drugs bust you'd been involved in," she continues. "I figured he'd either been telling the truth, or Annie hadn't told me everything I needed to know about her son."

"Could be both, for all we know. Phyllis, could you tell me where Gene is now?"

"I had him hassling me about the old days, he's your boss ain't he?"

Live the life you want and find the answers you're searching for. Never stop being that pain in the arse that gets results, because the world's better when you're being a git who's fighting for a cause he believes in. Keep doing what you think is right, Sam. You can make a difference. You already have.

Gene texted Sam, this next message "Wanted to be coppers since we were kids in the 70s."

Ruth smiles; a soft, sad smile. "Then you've got nothing to worry about, 'cause you both always keep your promises."

He and Gene leaves Ruth's terraced house with letters and the photographs. The evidence, so to speak. It's the least he can do.