Disclaimer: I don't own AMC's The Walking Dead or any of its characters, wishful thinking aside.

Authors Note #1: The idea for the pairing itself was inspired by 5x15 when Rick pulls his gun on the bystanders during the fight with Pete. I was interested in Nicholas' actions, where instead of backing away or pulling Tobin in front of him, he protects Tobin, laying his hand on Tobin's chest and actively pulling him away as he steps back.

Warnings: Spoilers for 5x15 and vaguely for the rest of the season in terms of canon character deaths. Meant to fit in a few months after the events of the season finale. Set in the Sentinel/Guide trope universe where Tobin is a Sentinel: a person with enhanced senses. And Nicholas is a guide: a person that helps a Sentinel control their gifts and keep them from 'zoning' or hyper-focusing on one sense and thus vulnerable. Something, which in more severe cases, can lead to death. The connection or bond between a sentinel and guide is a soul deep and almost spiritual thing that is generally considered pre-destined. Much like the soul-bond/one-love trope. *Contains: slash, adult language, adult content, possible consent issues – could be considered dub con due to the trope but nothing serious, mild classism: Sentinels often have a privileged status over that of guides despite the fact that there is a shortage of Guides per Sentinel. Deals with issues of drug-use and addition. This story doesn't touch on the fact that Tobin was revealed to have a family in the finale. – This chapter will be told in Rick's point of view.

Metronome (the piece of me I wish I didn't need)

Chapter One

"I found it the other day while I was out with Spencer and Rosita on that supply run," Glenn explained, standing over the remains of a small fire. Cold and sable black in a shallow, hand dug pit at the base of a gnarled oak. It was tucked into a small notch of trees, protected from view from all sides but one. Downwind. Perfect for someone with something to hide.

"The coals were still warm when I found it. This close to the wall? Has to be one of ours," Glenn continued, watching him sink down on his haunches as he used a stick to prod through the singed edges of burned packaging. Colt Python digging into his side as he kept one hand on the snaps of his holster. "Figured you'd want to see it."

"Yeah, looks like we have a problem, alright," he replied, the words coming out in a slow, rolling drawl as he unearthed a small vial, distracted as he tried to make out the label.

"Rick, this is serious," Glenn insisted, looking around suspiciously before catching his gaze and holding it. "If there's someone using in there…they're probably making it inside. That's dangerous. Crack. Meth. All it'll take is mixing the wrong chemicals at the wrong time and- well, you've probably been to those crime scenes."

"More than once," he responded, raising a brow when the flash of a familiar name caught his eye. An experimental drug with an unpronounceable name, then another and another. An empty bottle of cognitive blockers, a handful of indistinguishable, burned-out papers and an empty travel-sized container of codeine-laced painkillers.

No. It couldn't be. That would mean-

He abandoned the stick and dusted off the label of the first package, mind racing. Already mentally reviewing every person he'd spoken to. Every piece of interaction. Every off-center little tell he'd noticed from every member of the community he'd gotten to know over the past few months. Everything. Only to come up blank.

"We can't afford a junkie on the inside. Things are unstable enough after losing Reg and Pete…we're barely holding it together as it is," Glenn added, running his hands through his hair with a sigh. Looking back in the direction of the walled town with a tired sort of firmness. Like he was calculating the variables, trying to figure out the best course of action, the best play even though he'd clearly missed the most integral part of the puzzle.

He wasn't surprised.

Most people wouldn't.

Most cops wouldn't either.

"No, it's worse than that," he shared, tone thick with an almost conversational sort of slowness as he eased himself back to his feet. Feeling the strain in his kneecaps despite the fact that he swallowed the grunt. Radiating forced calm as he cycled through the options, one after another, sparing the younger man a significant look when Glenn rounded on him.

"Worse? How can it get worse than having some crack-head with access to the entire gun lock-up and god knows what else inside the walls when-?"

"We aren't dealing with a junkie. This is home-made guide in a bottle."

The silence was perfect. A deafening cymbal of nothingness as Glenn's lips fish-tailed. Stuttering. And honestly, he was right there with him. From what he'd gathered over the past few years - clips of conversation heard mostly in passing from the others during the quiet nights, fireside - was that while he was in coma, when things got bad, the Sentinels had been on the front lines, together with their guides.

Almost every city had been host to a final stand. Whether it was ordered by the Tower or not. It wasn't in a Sentinel's nature to run. So when the cities fell, the Sentinels went down with them. Burning away into obscurity, like a final swan song of an already dying genetic code.

Sentinels. Guides. Bonded Pairs. All of them. Gone.

Lori had told him – hushed and pale in the privacy of their tent not that long after they'd been reunited – how Atlanta's Alpha Sentinel and Guide pair had still been out on the streets, helping those who'd been left behind try to evacuate – holding the lines with what was left of the military when the Governor had given the order to firebomb the city. They'd refused to leave. Even when all hope of saving Atlanta was gone. And they hadn't been the only ones. All over the country, it had been the same story. It was like, with one fell swoop, America had been cored out.

Even now the loss was hard to swallow. Hard to contemplate. It was sorrow without measure, priceless in the insurmountability of their loss – their absence. Sentinels were rare. Guides even more so. Bonded pairs? Times that by a couple hundred thousand and then some. But Alphas on top of it? Well, let's just say that not even D.C had a bonded Alpha pair.

They had been bonded since they were teenagers. One of the lucky few who'd found their fated first try. And it was little wonder. From what the Tower boasted, they'd practically been made for each other. Both strong and fully online. Mirror images of the other in terms of ability and strength. Quickly outpacing their peers as the beauty of their partnership eventually inspired thousands around the state to willingly sign up for Guide aptitude testing.

He'd grown up knowing their names, everyone did. He'd even met them in passing, when they'd toured the new station house in King's County after all the renovations a few years after he'd come on. The two women were rarely out of each other's sight, hand in hand, smiling and proud. Openly affectionate and equally as fierce as they patrolled the city and the surrounding suburbs – their official territory – with the unwavering loyalty of any large predator.

But the thing about Sentinels is that they aren't supposed to be alone.

A Sentinel and their Guide were a matched set. Balanced and strong.

But a Sentinel by itself? Full-grown? Well-

Glenn took a breath, pushing out the vestiges of the old like he was moving mountains. Extending a hand to take one of the half-melted containers as he crouched back down and started salvaging what they could to take back with them. Knowing Deanna was going to want to see it laid out before Glenn finally came to terms with whatever he was chewing on and fixed him with a piercing look.

"But that means…."

His expression felt grim on his face, the opposite of what it probably should have been as it pulled back his lips to show his teeth. A hard line of plaque-stained ivory, sharp, uncompromising and just the tail-edge of vicious as he followed Glenn's stare back through the trees.

"There's a rogue Sentinel in Alexandria."

A/N #1: Thank you for reading. Please let me know what you think! Reviews and constructive critiquing are love! – There will be more to come, stay tuned!

Reference:

*Bonded: The Sentinel/Guide relationship is a lot like the soul bond/soulmate trope. In my version of the trope there is one perfect Guide for every Sentinel and one perfect Sentinel for every Guide. Being a bonded pair means you are with your 'soul-mate' and are the strongest Sentinel/Guide you can be because you are 'complete.' In my version of the trope, a bonded pairing is also a sexual and romantic partnership.

- However, like in most versions of the Sentinel/Guide trope, Guides are present in society in much lower numbers than there are Sentinels (who also make up a very low percentage of the population), so finding your bonded is very hard. Often Sentinel's must settle for the next best thing, or accept shallow platonic substitute bonds with temporally assigned Guides until they find their match. This is not ideal and often leads to problems.

*Alpha pair: The strongest bonded pair in a particular area. Meaning, usually, all five senses are active within the Sentinel and the Guide had strong emphatic abilities. They are considered the Sentinel/Guide authority in that area and often are considered up there with the Governor or Mayor of a particular state/city in terms of power and position.

*The Tower: Is a fandom creation that is the managing system for Sentinel's and Guides. Often where they are trained, discovered, paired and managed. Like a connecting Government body, the Tower acts like any other facet of the government – specific in terms of dealing with Sentinel and Guide related matters.

- In many fics it is seen as a corrupt entity that abuses Guides and sees them as second-class citizens - more the property of their Sentinel than people in their own right. However, in my story, that is not fully the case. There are some hints at the Tower's not so shining history when it comes to Guide-related matters, but mostly it has been revamped into something 'better' in the modern age. Though the residual history still affects people's opinions regarding it. Something which is probably not helped by the fact that due to the Guide shortage the Tower pursues potential guides fiercely and once a guide has been discovered, they have little choice but to be trained and assigned along with their peers.

- It is important to point out that there is a power imbalance here. While Sentinel's are the ones with the power and physically manifested strengths, they need their guide. Bonded pairs need each other mind you, but a Guide doesn't need a Sentinel the same way as a Sentinel often needs a Guide just to function. Most Guides are empathetic, very in tuned with their emotions and the emotions of others but unless they have sensed their bonded, they don't feel the pull to need a Sentinel in their everyday life. Sentinels on the other hand, have a hard time functioning in everyday life after their senses come online – which for both Sentinels and Guides is around the age of consent – 17-20 years of age.