Author's Note: Hey, thanks for checking out my first MacGyver story! I am *OBSESSED* with this show, I think I blew through the 3.5 seasons that are out in like a week when I should have been working on my thesis (oops?). Anyway, thanks for clicking on it, if you like it, click like and hey, reviews are always appreciated. Xx

Fully Summary: At the diner, Riley said Mac and Jack have "serious codependency issues" and, well, she's not wrong, but she doesn't know the whole story. So here is one potential way she finds out about the boys' history, and why they are so "codependent" on each other. Set at the very end of episode 4x7 (Mac + Desi + Riley + Aubrey), but mostly concerned with the events revealed in episode 2x12, Mac + Jack - DEFINITE spoilers for that episode.

Disclaimer: characters are not mine, I'm just borrowing them; I'm not making money from this; etc., etc.

"Riles."
"Hey...Aubrey ended it. Couldn't stay at his place...I didn't know where else to go. So."
"I'm so sorry. Well, you're more than welcome to stay here as long as you want."
"Hungry?"
"You have *no* idea."

Mac wasn't great at emotions – his own, or other people's – but this was Riley, and he was going to do his damnedest to be there for her, whatever she needed, whether it was a place to stay, a friendly shoulder to cry on, or someone to build matches and burn stuff with.

Mac, takeaway bag in hand, led Riley to the living room. Riley flopped down on the couch, which was oversized leather and extremely comfortable, and curled up. Mac sat down next to her, setting the bag on the coffee table and getting to work opening the containers.

Grabbing the remote, Riley called up Mac's Netflix account and started browsing.

"You're only on season 2 of Game of Thrones?" she asked, shocked.

Mac laughed and rubbed the back of his neck. "We don't exactly get a lot of downtime."

"Even Jack is caught up, Mac, you're just falling behind," Riley teased. "Come on, we're watching this."

Mac gestured for her to go ahead (not that Riley needed an invitation, she did what she wanted and had, in fact, already pressed play) and reached out for a container of Chinese food and a pair of chopsticks. He passed it over to Riley, grabbed a container and the other set of chopsticks, and settled into the couch cushions himself.

As they watched, they would trade cartons, or switch them out from the collection on the coffee table periodically. At one point, Mac got up and got them water bottles from the fridge – which were about the only things in his fridge. He made a mental note to go grocery shopping in the morning.

Jack had always worried about Mac's lack of appetite, but the truth was, Mac loved food, he just forgot to eat when he was hyper-focused on a problem or a mission. It was a side effect of his ability to compartmentalize and analyze problems. He would feel hungry as he worked, but other things took priority and so he ignored the feeling. But now, after the adrenaline rush of the fight, the lack of "real" food for dinner, and his head buzzing with questions about where exactly he and Desi stood, he could admit that he was just hungry, and tired. And now Riley was here, needing a friend and bearing food as a gift, and who was he to look a gift horse in the mouth?

Together, they polished off the Chinese food in the time it took for the show to end. Feeling sated, but mind still whirring, Mac let himself sink into the couch cushions. Out of the corner of his eye, he saw Riley do the same.

"Do you want to watch another, or do you want to sleep? I might have wine, somewhere, or –"

"Mac, stop," Riley said, smiling. She gave Mac a gentle, affectionate shove. Her smile faded a little. "I don't want to watch anymore, but. I'm not ready to sleep, either." She was tired, but she didn't want to be alone just yet. "Can we just…talk?"

Mac turned his head so he could look at Riley fully, studying her for a moment. Her eyes were no longer glassy with unshed tears, like when she had appeared on his doorstep, but she was frowning slightly, watching him closely.

"What do you want to talk about?" he asked. He was growing drowsy, especially after all that food, but whatever Riley needed from him, he would do his best to give.

"I dunno…" Riley trailed off. She couldn't look at Mac's earnest eyes anymore and turned to stare at the Netflix home screen, blinking rapidly. One of the titles Netflix was suggesting Mac watch caught her eye – American Sniper. Below it, in the list of shows in progress, was an old episode of Mythbusters. Seeing the two so close together sparked a memory. "Hey, remember that time you asked me to be Jack?"

Mac frowned, thinking back. "At the diner, yeah. Yeah, we were cornered and –"

"And you asked me to tell a long-winded story that doesn't seem to go anywhere or have a point."

Mac nodded. "Like Jack," he said softly, the sense of grief at his absence hitting him suddenly and intensely. He forced a laugh to dispel the sadness. "You called us codependent."

Riley laughed with him. "Cuz you are," she said. She sobered, though, watching Mac. "But, y'know, I've watched you guys, seen you guys in the field. You guys can practically read each other's minds during missions – it's almost scary." Riley paused and studied Mac closely. "How did you guys get there?"

"You mean like how did we meet?" Mac asked, confused.

"Yeah. Like, I know you guys met in the Army or whatever, but like. You two don't really have much in common, y'know? I mean, Jack is so old," Riley attempted to soften what she realized was an invasive question, "how did you guys become…you guys?"

Mac propped his feet up on the edge of the coffee table and let his hands rest on his knees. He sighed, then laughed and rubbed the tops of his thighs, remembering their first encounter.

"Like you said, we met in the Army," he began. "But there's a lot more to it than that." Mac closed his eyes and tipped his head back, the memories flooding him.

"I had just been sent to my first solo post as an EOD specialist. I'd been in Afghanistan for 6 months already, but was still under the supervision of my mentor, Alfred Peña…" Mac trailed off, remembering Peña's death.

"I'm sorry, this is really personal, I shouldn't have asked you to remember all this painful stuff," Riley whispered.

Mac looked over at her. "I'm okay, it's okay," he reassured – whether for Riley's benefit or his own, he wasn't entirely sure. "Um, right. So, Peña had just been killed, and I'd been graduated to solo work. Right. Well, I got to the base they assigned me to and the first thing I did was try to find my bunk, so I could put my stuff away and then go for a run."

"You went running in the desert?" Riley asked.

"It helps me think," Mac gave a wry grin. He knew how crazy running in such conditions sounded. "Anyway, I found the tent I was assigned to and grabbed the only bunk left, which was the top bunk all the way at the back." It was every soldier's least favorite place, for the inconvenience of having to go up and down the ladder to get to it, and being the furthest away from the door, where there was occasionally a cooling breeze.

"I had just set my stuff down and was on my way back out when I saw a rifle on the floor next to one of the other bunks. I was just gonna put it back on the guy's bed, but then I noticed the scope was slightly off and figured it must have fallen off the bed or something and gotten messed up. Either way, I started to work on it, resetting it, and then noticed there was something wrong with the forward assist and started working on that, when suddenly," Mac laughed and shook his head.

"Jack?" Riley asked, Mac's laugh infectious.

"In the most Jack way possible," Mac said grudgingly. "He punched me."

"Whoa, hold up a second," Riley interrupted. "Jack. Our Jack. Jack Dalton. Punched you?"

"Right in the jaw," Mac said, rubbing the spot like he could still feel the sting. "He's got a wicked right hook."

"What the hell."

"I mean, now, I can see it from his perspective," Mac admitted. "Some guy he didn't know was touching his sniper rifle, sabotaging it for all he knew. And you don't…" We don't ever – EVER – touch Jack Dalton's stuff, "you don't touch a sniper's rifle," Mac said. "They get…touchy about it. Not exactly superstitious, just…it's a private, personal thing, a sniper's own sniper rifle." Mac struggled to describe the relationship those soldiers had with their weapons, but found the words to describe it eluded him. He waved his hand, still trying to explain. "Like you don't go up and touch a stranger's baby without permission. Sort of." He settled for that.

"I think I get it," Riley said, nodding.

"For a sniper – especially one of Jack's caliber – the rifle becomes like another limb, intrinsically part of them, of their very identity," Mac added.

"So you touching it without his permission –"

"Let's just say it struck a nerve," Mac said, lips quirking.

"So what did you do?" Riley asked. "After he…punched you." She still couldn't really wrap her head around the idea of Jack laying a hand in violence on Mac. In fact, for all the times she'd seen Jack hit people, her mind refused to conjure a mental image of him doing so to Mac, it was that…wrong.

"Well, first I hit the floor," Mac continued. "I think I bit the inside of my cheek, I just remember spitting and seeing blood on the floor of the tent. After that, it's a bit of a blur."

"Jack hit you that hard?" Riley asked, concerned.

"More like hit me that fast," Mac corrected. "As soon as I got back up, he came for me again. Then, I just sorta went into survival mode, trying to block him. They teach you hand-to-hand combat in basic, and I was pretty okay at it, but Jack is –"

"A trained badass."

"Exactly. He had a decade of experience, as well as about 60 pounds on me. Plus, he was mad as a hornet, and you know how he gets when he gets in the zone."

"Kind of like you do with a puzzle."

"Yeah. So at first, I tried to just block. But as time went on," Mac remembered it felt like years, but was actually just seconds, "I picked up his style, started almost anticipating his moves. Once I did that, I was able to get a few good hits in, myself."

"I would pay good money to have seen that," Riley said, grinning.

"The other soldiers in our bunk thought the same, because I remember hearing cheers and shouting," Mac recalled. He shook his head. "I was so focused at the time on not getting beat to a pulp, they sounded very far away."

"So who won?"

"I think technically neither of us did," Mac said, frowning. "I had Jack in a wrestler's throw, but he'd flipped us and was about to I'm sure knock me out cold, when our CO came in and forced us apart, demanding an explanation."

"And what did you say?"

"Before I could say anything, Jack started accusing me of messing with his rifle, so I tried to explain what I was doing, scientifically –"

"I bet that went over well," Riley snorted.

"Ah, yeah. Point being, neither of us got a whole explanation out before the CO decided breaking up fistfights between his soldiers wasn't worth his time and introduced us to each other as partners."

"Wait that's it?" Riley asked. She turned and glared at Mac.

"What?" he said, defensively.

"Come on, Mac. You didn't just shake hands and were best friends from there on out. Tell me what happened," Riley said.

Mac sighed. "You're right. We were not friends – at least not yet… Our first month of missions was…tense, to say the least. I worked slowly, being careful and taking my time defusing each IED. I didn't want a repeat of what had happened to Peña."

"Did Jack know about Peña?" Riley asked when Mac paused.

"Sort of," Mac hedged. "He knew that Peña had died while he and I were on a job. In fact, he accused me of letting him die on my watch, right after our CO had broken up our fight."

"That doesn't sound like Jack."

"It was just a cheap shot. I called him some unflattering things in return, if it makes you feel any better," Mac said, rolling his eyes.

"Actually, kinda," Riley admitted. Mac gave her a look. "What? It's nice to see you stand up for yourself – even if it's against Jack," Riley explained.

"Uh, thanks?" Mac said, but it sounded more like a question.

"I'm just saying, Bozer told me about how you and he met, and it sounded like you've had quite the history with bullying. I'm glad you can stand up for yourself now."

Mac smiled and held his arm out, inviting Riley to lean against him. She did, bringing the blanket from the back of the couch with her and covering them. "I appreciate that, Riles," Mac said softly.

"Of course, Mac," Riley said. "Now, get to the part where you become Mac and Jack."

"Right, um…" Mac rubbed his chin with his free hand, gathering his thoughts. "We clashed a lot, but when you're an EOD tech and his bodyguard, friction like that can get you killed – so easily. Jack actually saved my life after one particular clash. We were clearing a village that reportedly had suspicious activity, and had been searching it all day but hadn't found any IEDs and Jack was itching to get back to the base. I had this gut feeling that we were missing something, so even though Jack radioed in saying we were coming back to base, I refused to leave. Since Jack refused to listen to me, I left."

"What?" Riley gasped, lifting her head so she could gape at Mac, who at least had the grace to look sheepish. He shrugged uncomfortably and urged Riley back onto his shoulder.

"I couldn't walk away from the village and potentially let a bomb kill innocent, civilian lives," Mac explained. "Since Jack didn't want to listen to reason, I went in search of the IED myself." He sighed. "Turned out to be one of the dumbest things I've ever done."

"Why, what happened?" Riley asked.

"Well, I found the IED – it was a cooking pot, all taped shut with wires sticking out of it and a timer on top, tucked behind a barrel in the back of some house. As soon as I saw it, I kneeled down to get to work disarming it when I felt a hand on my shoulder, pulling me up and spinning me around. I thought it was Jack, come to drag me from the village back to base himself."

"But it…wasn't Jack," Riley guessed.

Mac shook his head. "I turned and there were four men, dressed head to toe in black – insurgents, not soldiers."

"What did you do?"

"I froze," Mac admitted. "I had walked away from my Overwatch and straight into trouble. I thought I was going to be shot right there."

"Well obviously you weren't – you weren't, right? You're sitting here, so you didn't get shot. Unless you did get shot just not killed, but that's just as equally awful as –"

"I didn't get shot," Mac cut Riley off before she could worry too much. "In my head, I was trying to calculate how many men I could take before one of them shot me. But before I got much past trying to estimate body mass times acceleration on the first guy, I heard a gunshot."

"You said you didn't get shot," Riley said, confused.

Mac smiled. "I heard a shot, and the two men in front dropped like stones," he explained. "And before I could process that, there was another shot, and the other two men also dropped dead."

"Wait…"

"I figured out the angle the shots had come from and looked up at the second story window of the house next door and saw Jack behind his sniper rifle, chewing a stick of gum like nothing had happened."

"He killed four guys with two bullets?" Riley asked, not sure she could believe this story anymore.

"That's exactly what I asked him over comms," Mac said, laughing.

"What did Jack say?"

"He goes," Mac put on his best Jack-impersonation, "'Yeah, I'm tryna conserve ammo. You almost done here?'"

"Oh my God, Jack," Riley snorted, laughing at Mac's attempt at a Texas drawl as well as Jack's comment – which was just so, so Jack.

"After that, we worked together a lot better," Mac said, smiling.

"I can imagine," Riley said drily. She sighed, and let the silence wrap around them while she thought about what Mac had told her. Then she frowned. "Wait, I thought Jack was the one who owed you the Wookie life debt?"

"After that, things were different. I mean, Jack and I got along better and stuff. But truth is, we ended up saving each other's lives, too many times to even count. But you asked how Jack and I became Jack and I, right?"

"Yeah…"

"Well, that save taught me two things. The first was that Jack had my back, no matter what I did. I could even walk away from him, and he would still come for me. And that's…" Mac sighed heavily and rubbed his forehead. Emotions were hard. "I mean, it's no secret I've got abandonment issues," he tried to say it lightly. "My mom dying when I was five, dad leaving when I was 12, grandpa dying when I was 18… Peña being killed…"

Riley grabbed Mac's hand and gave it a squeeze. He smiled down at her in return.

"But Jack came back for me. And that, well, it just…it meant a lot. More than I can really put into words." Mac gestured with his free hand. "So that…that was it for me – the turning point, I mean. I began to trust Jack not only with my safety, as my Overwatch, but trust him more personally."

"But what's more personal than trusting someone with your life?" Riley asked, trying to understand.

"Like I said, we saved each other's lives all the time. It's not really that uncommon amongst soldiers, it's just what soldiers do, looking out for each other. But it doesn't always mean that they like each other. Does that make sense?"

"Yeah, I think so." Riley frowned, thinking. "You said there were two things."

"Right," Mac said, getting back on track. He gathered his thoughts, then began again. "Jack came back for me, showed me I wasn't on my own no matter what. But taking out four guys with two bullets was…an insane amount of marksmanship. Even at the close range he was at, the skill such a shot would require – and not just once but twice – it showed me that Jack was exceptional."

"Exceptional," Riley repeated. Even for Mac, that was a strange word to use.

Mac caught her picking up his vocabulary choice. "It's what they call the gifted kids, in school," he said quietly. He sighed. "I got called it plenty, by science and math teachers all through school. 'Exceptional.'" He snorted derisively. "I would have preferred to be normal."

"You don't want to be super smart?"

"That's not what I said," Mac defended. "It's just that, when words like 'exceptional' and 'gifted' and 'special' are bandied about, people suddenly start expecting exceptional things from you."

"Like when you defused the twin bombs," Riley said quietly.

Mac nodded. "Yeah, that's one of just many examples. As soon as I was labeled 'exceptional,' people started expecting me to do these impossible, amazing things – solve impossible problems. It was…a lot of pressure."

"So what does Jack have to do with it?"

"Those two shots made me realize that, like me, Jack was exceptional, just in a different way," Mac explained. "I could defuse bombs, solve problems, calculate formulas in my head and on the fly, but Jack could complete impossible shots under immense pressure, solve an impossible problem – albeit in his own, very-different-from-mine way."

"You realized you had an equal," Riley said, nodding.

"More like a complement, but yeah," Mac agreed. They sat in silence for a moment, though it wasn't an uncomfortable one. "All my life, people expected great things from me, without really considering the consequences – or considering them and judging them worthwhile. But Jack… Jack was the first person I met who fully understood the weight of others' expectations in the face of impossible odds because he carried the same weight."

Riley thought about that for a moment. "What about Bozer?"

"What about him?" Mac countered.

"You two were friends since you were 10. Couldn't you talk to him about the weight?"

"I tried to, once," Mac admitted. "He tried to understand, and he certainly felt bad for me and tried to support me any way he could – helped me with my for-fun science projects and whatnot. But I could tell he didn't really get it because he didn't feel the weight himself, didn't have a concept of it, really."

"I suppose that makes sense."

"Yeah." Mac sighed and squeezed Riley's shoulders with the arm that was around her. "From there, I guess I just started relying more and more on Jack. But, instead of being a weight of expectations on each other, we became a team, sharing the burden of others' expectations and carrying it together."

"And you became Mac and Jack."

"Well, it took some time, and some sacrifices, but yeah, basically."

"What sort of sacrifices?"

"When I met Jack, I was just beginning my tour of duty," Mac explained. "Jack, however, only had 64 days left and was then going to walk away. The man had more than earned it. He did his standard army duty, then had a couple rotations on Delta force, a stint with the CIA, and then was back overseas again when I met him…"

"Whoa," Riley breathed.

Mac quirked his mouth. "Never let it be said Jack Dalton does anything by halves, either."

"Seriously," Riley muttered. "If the weight of expectations is related to how much work he did for the military then…"

"Then his weight of expectations easily matched mine," Mac finished for her.

"You said Jack only had 64 days left when you started," Riley said. "How did you have time to build up to your superhero status?"

Mac grinned at what was one of his favorite memories of Jack. "Well, Jack left the base to go home, and I was sitting in my Humvee, waiting for my next Overwatch to arrive, when suddenly someone slapped the window ledge of the passenger door and said, 'What kinda name is Angus?'" He did his Jack impression again. "And he climbed right into the Humvee next to me and said he had re-upped, under the condition he and I worked together exclusively. After that, we made a real name for ourselves. We were the most sought-after EOD team around."

"And you became Mac and Jack, bomb disposal superheroes."

"Yeah, I guess," Mac laughed. "We each found someone who understood us, and turned it into our strength."

"But Jack barely understands your science speak," Riley pointed out. "Half the times he just tells you to shut up."

"He may not understand the words I say, but he understands the process I go through, and the pressure I'm under," Mac explained. "And really, that's all that matters to me. I don't need someone who understands my 'science speak,' I need someone who understands me." Mac sighed. "And that was Jack."

"Even with his stories that have no point and don't go anywhere?" Riley asked, trying to lighten the suddenly heavy atmosphere.

"Yeah," Mac said, smiling. "I know it sounds crazy, but…I guess it was Jack's way of letting me know he was there."

"By not letting you forget the sound of his voice?" Riley joked.

"Yeah, I mean – you've seen how hyper-focused I can get on a problem. Jack's voice became a way for me to…I dunno, ground myself, I guess, when I get too inside my own head, thinking." Mac flushed a little at how nerdy he sounded, even to his own ears. "I mean, it took time for us to develop the system you've seen us using since you joined our team, but yeah. Jack keeps me from forgetting the real world while I work on problems. And I understand not only the weight of expectations people have of Jack, but the darkness that comes with his particular burden."

Riley looked up at Mac curiously. He glanced down, caught her look, and sighed. "Jack's killed a lot of people, Riley," he said quietly. "I know he puts on a good show, but he has his demons, same as me."

Riley nodded sadly. "I knew he'd killed people – I mean, I've even seen it with my own eyes, on missions…I guess I just choose not to think about it, you know?"

"I do," Mac said. "It's easier to pretend it doesn't exist. But like the rifle is part of the sniper himself, so are his kills. Each one takes a little part of the soul."

"And Jack's killed a lot," Riley added. "I can't believe I never thought about this before."

"Jack doesn't want you to worry about him. They're not my stories to tell, but Jack has plenty of nightmares. Sometimes, he needs someone who gets it to pull him out of them."

"Like his stories while you work pulling you out of your head," Riley said.

"Yeah, kinda," Mac agreed.

"So basically, you guys take the brothers-in-arms, battle buddies thing, but compounded it with this burden of exceptionality," Riley said, trying to wrap her head around what Mac had told her. "Then you continued building on that by returning to the brothers-in-arms thing, shoring up each other's weak spots – you getting too into your head and Jack's, what, PTSD?"

Mac fidgeted. This was the closest anyone had bothered to really examine his and Jack's relationship, except for the cursory check DXS had done to make sure they could work effectively together in the field when they'd first been hired.

"Mac, I love you, but I stand by my codependency comment," Riley said, unable to resist ribbing him, just a little. It worked; Mac laughed. "But," she said. She grabbed his hand and looked up at him, her voice serious. "I do take back the judgement, though. I can't even begin to imagine the kinds of things you two have been through together, and you have every right to be attached to someone who gets you like no one else does. I'm sorry."

"Riles, I appreciate it, but it's really alright," Mac said, flushing again. "We shouldn't have relied on each other so heavily; it does make it that much harder to work independently, to not have that safety net of a person."

"Yeah, but I see why now," Riley argued. "And it's like Matty said – we work best with the people we love."

Mac gave Riley another squeeze. "Thanks, Riles," he whispered.

"I didn't mean to bring up such a touchy subject," Riley apologized again. "But, now that I know, maybe I can…not be Jack, but be me, and be there for you, too?"

"That would be nice," Mac agreed. "And hey, I'm here for you, too, you know?"

"Yeah, I do know," Riley said, snuggling into his side and closing her eyes.

Mac rubbed her arm as they sat in silence, just being there, together, for each other. Jack was gone, and Mac had no idea when he'd come back, and Riley was there, and needed a friend, and he could do that for her. It wasn't that he didn't need Jack anymore – far from it, he felt more lost than ever without him – but Jack wouldn't want him to beat himself up over his absence. He could almost hear Jack's drawl in his head, telling him to stop worrying about him and focus on what was present and real around him. Riley, Bozer, Matty, Desi – they were real, and present, and needed him at the top of his game. He would keep Jack in his heart, but until Jack could return, he'd just have to do his best without him. And he could start here and now, with Riley, who needed a friend and a place to stay after their work as secret agents ruined another relationship.

He closed his eyes and let sleep take him. He could be that friend.