AN: Bit of a lighter chapter this one, as I wanted to explore Eren's reaction to AMs change (he obvs doesn't know the truth yet). Enjoy.

It's well after midnight when Armin finally sees the camp's outer fence. Exhaustion had set in a while back, his legs shaking like blades of grass in the wind. He had to carry the unconscious Mikasa the whole way back from that clearing.

Just like Eren and himself after their initial transformations, she had passed out, and nothing seemed to wake her. Eren had told him that he had been unconscious for several hours after eating Bertholdt and Eren was out of it for nearly a day after the battle of Trost.

Armin knew there would be chaos when Annie was reported missing, and if anyone noticed and reported their absence during the night, they would be in serious trouble. They had to get back as soon as possible to avoid any suspicion.

Unfortunately, being the only conscious member of the pair, it fell to him to get them back.

Armin didn't want to call Mikasa 'heavy' (he knew that calling any girl that was a surefire way to meet a very messy, very painful end and he did actually value his life, thank you very much), but in his 13-year-old body Armin simply didn't have the strength to easily carry someone on his back for hours.

With a huff of relief, he forced his legs to move, covering the distance between the edge of the woods and the fence with painful slowness. "Come on," he thought to himself "Only a few more minutes. We're nearly there."

Several tiring minutes later he finally reaches the barracks, only to realise he had another problem. Mikasa was still unconscious; her slow breathing and body heat were her only signs of life for the last few hours. He couldn't just leave her outside, and he couldn't bring her to the boy's dorm in case Shadis saw her in the morning, leaving only one option left to him.

Armin would have to sneak into the girl's dorm…

With an unconscious person on his back…

Without being seen or heard…

And get Mikasa in her bed.

He let out a long-suffering sigh, "The boys would never let me live this down if they found out." He thought; half resigned, and half-amused, "Or they would demand I tell them everything."

Shaking his head, he started to move towards the girl's dorm.

There are many words that can be used to describe Eren Yeager; Angry, determined, headstrong or, as Jean would say, suicidal. But one people didn't use to describe Eren would be observant; in fact, the boy sometimes had a supernatural ability to miss the obvious.

It had been a long day of training as Eren wearily made his way, food tray in hand, to a table. Slumping down on his seat, he began to dig into his bland, tasteless dinner. The two years he had lived as an orphaned refugee had taught Eren never to waste food and to treat every meal as if it were the only thing he might get that day.

True to form, Eren had managed to consume half his dinner before noticing that Mikasa and Armin hadn't joined him. Confused, he looked around the canteen wondering if they had sat elsewhere or been caught behind Sasha in the queue (it was well known amongst the 104th cadets that getting stuck behind Potato girl at dinner was a rookie mistake. She would try every trick in the book, from begging to bartering, trying to scrounge more food from the kitchen staff).

As if his confusion had summoned them, his missing friends suddenly walked in the mess hall quietly chatting to one another. Catching Armin's eye, the blond smiled and gave Eren a small wave before they joined the dinner queue. Satisfied with his friends' whereabouts, he went back to eating, bringing a spoonful of broth to his mouth.

"Do you think they're dating?" Eren looked over to the neighbouring table where Mina, Thomas and Hannah where sitting.

"Those two? Nah. What makes you think they are?"

"Well they always seem to be together, and Sasha swears she saw the two of them sneak behind one of the storage huts." Mina said.

Eren quickly lost interest, annoyance building within him. They were here to be soldiers and learn how to kill titans, not to gossip about crushes and who fancied who. It irritated him enough when he heard it in the boy dorms, the same stupid conversation over and over again; "Who's do you think is the hottest?", "Who's got the best arse?" or another round of 'Kiss, Marry, Avoid'.

"Pfft, I doubt it, the only thing Sasha ever pays attention to is food." Thomas was interrupted as Mina smacked him over the head. Rubbing the back of his head before continuing "Ow Mina, that hurt. Anyway, isn't she kinda obsessed with Yeager?" Despite his previous thoughts on the matter, Eren couldn't stop himself from listening in.

"Not anymore, I think she realised it was unrequited. Poor girl." Replied Hannah, the resident expert on romance, thanks to her ongoing relationship with Franz.

Before Eren could demand they tell him who they were talking about Mikasa and Armin sat down next to him. Armin apologised for being late, informing him that Shadis had wanted to speak to them.

Eren felt a brief flicker of jealousy pass through him; both Mikasa and Armin seemed to be excelling with their training, quickly distinguishing themselves from the other cadets with both their 3DM and weapon skills. Eren had been improving, but nowhere near as quickly as they had. It made him feel inadequate, knowing he was the least skilled of the trio; he needed to get better and stronger if he was going to protect them and kill all the titans.

The moment soon passed, and he returned to what he had overheard Thomas says. "Who would be obsessed over me? Did one of the girls liked me?" the questions ran through his mind. He couldn't think of who they could've been talking about, "I talk to Armin about it, he'll know.".

He turned to speak to them when he was abruptly interrupted.

"Good job fighting Annie today, Yeager. Maybe one day you might win!" Jean Kirstein jeered from across the hall.

"Why don't you come over here and say that, Horseface!"

And like that Eren had wholly forgotten his plan to speak to Armin.

Eren knew he had probably had too much to drink, but Horseface had challenged him and Eren would rather headbutt a titan than let a challenge from Jean go unanswered. Even something as small as a drinking game, he wouldn't concede to him.

He swayed in the busy Trost pub, he had beaten Jean (who had passed out onto Marco) and was celebrating his victory with another drink. His whole body lurched forward as an arm wrapped around his shoulders, "That was some fine drinking there Eren, put Jeanie boy back in his place!" a drunk, red-cheeked Reiner chuckled beside him, drink in hand. "Say, where's Armin and Mikasa?"

Eren jovial mood disappeared, "They didn't come, they said they already had plans." He sneered at the last word, he was still annoyed at his friends, one of the few times they get the chance to leave bootcamp, and they refused to go.

But this only made Reiner laugh some more, "Haha, yeah, I bet those two had 'plans'."

"What's that supposed to mean?"

Grinning, Reiner replied, "Come on, Eren, you don't have to cover for them with me. I can see what's going on."

"Reiner, what the hell are you on about? Covering for what?" Eren stared at the 'blond behemoth' as Connie had once nicked named him, thoroughly confused.

Reiner's grin slowly died and disappeared of his face "Wait, you don't know? Oh…"

Eren's patience finally ran out, "Stop being an idiot Reiner, what don't I know?!"

Throwing his hands up in surrender, Reiner calmly says "Woah man, calm down. I'm just asking if Armin and Mikasa are… together ya know, like if they're dating?"

Eren's mouth dropped, staring at Reiner in shock. Of all the things Reiner could have said that was perhaps the most unexpected, Eren probably would have been less shocked if Reiner had told him he was half titan or something.

"I... What? Why would you think that? They're not dating, or they would…" Eren's words died in his throat. What would dating people do? He thought about Hannah and Franz, the only confirmed couple in the 104th, and how they acted.

They were constantly together; during training, meals and free time. If you saw one, the other wasn't far behind. Just like Armin and Mikasa.

They worked well together, trusting each other and coming to the aid of the other when needed. Just like Armin and Mikasa.

And they often sneaked off, leaving the other cadets behind without telling anyone. Just like Armin and Mikasa.

The more he thought about it, the more it explained their recent strange behaviour. Was it possible? Had they started dating without even telling him? Eren refused to believe that, surely, they would tell him if they were.

But he couldn't stop that little voice in his heading telling him that it made sense; it explained why they seemed so much closer than they had been a few months ago and why they were often late for meals.

No, they were just close friends, and Reiner was being stupid.

In a rare showing of self-control, Eren decided that he wouldn't immediately confront his friends when he returned from Trost over Reiner's words. But he certainly would be watching them closely from now on, and he would discover the truth.

True to his word, Eren watched his friends closely. They didn't seem to show any obvious signs of affection, like Hannah and Franz did.

There were no longing stares or excessive physical contact. But there was something, Eren couldn't quite put his finger on it, but it was there, some deeper connection that he didn't understand. He watched them during training, and whenever they were paired together, they seemed to know exactly what the other was planning. Even when Shadis was in an exceptionally bad mood (not that he was ever in a good mood), he could find no reason to criticise their performance.

This only fuelled Eren suspicions, they were clearly closer than he had expected and in his mind that pointing towards one thing… that maybe Reiner was right.

Eren had just finished his argument with Jean when he noticed that Armin and Mikasa had left the mess hall. He narrowed his eyes in irritation; they must have waited until he was distracted by Horseface to leave. He had previously decided to follow them next time they disappeared and maybe find out once and for all what was going on between his two friends.

Sasha had already helped herself to the remains of his meal while he was arguing. Seeing no reason to stick around Eren also stalked out of the mess hall.

As quickly and quietly as possible Eren sneaked from outbuilding to outbuilding trying to find his missing friends. He wasn't trying to spy on them, he told himself but was merely making sure they were alright without them noticing his presence, he was doing what any good friend should.

Yeah, he totally wasn't spying…

He was about to give up when he suddenly heard a familiar voice behind one of the storage huts.

"YOU DID WHAT!" Armin's near shout finally revealed their location to Eren.

Eren, unfortunately, missed what Armin followed up with as he crouched down on the other side of the hut, listening in.

"Calm down Armin, I was very careful." He heard his adopted sister whisper, curious about what had caused Armin to shout.

"That's not the point Mikasa! This is dangerous; we can't just rush into this." His blood went cold. What was going on? Were his friends in danger? Was someone threatening them? He was about to march round and demand answers when Mikasa replied.

"Armin, this is an excellent opportunity. When are we going to get this kind of chance again? No one would find out."

Confusion and concern warred within him. He knew Mikasa would never put Armin or him in danger; she used to mother them constantly when training started, so the idea that she would be seemingly encouraging something dangerous to Armin was a foreign one to him.

Armin was quiet for a few moments. Eren didn't need to see his friend to know he was thinking about whatever Mikasa had asked him. Eventually, Armin does reply.

"We'll need protection. We can't risk something going wrong."

Oh

Oh

An uncontrollable blush creeps up his face, as he realised what he's uncovered. As the son of a doctor and having recent sat through the standard military sex education lesson, (which consisted of a camp nurse explaining the bare-basics of reproduction, the different diseases you can catch and how to prevent pregnancy and said diseases, and was finished off by Shadis threatening to personally neuter anyone who even thinks about doing it) he could gather what sort of 'protection' they were talking about.

He had no idea what the hell to do, his brain not quite able to bridge the gap between what he's just overheard and everything he thinks he knows about Armin and Mikasa. But when Mikasa replied with a hum of approval, his body took control from his overworked brain, and he fled, hoping they didn't hear his rapid retreat.

After his discovery, Eren does everything in his power to avoid the pair without raising suspicions. An almost overwhelming sense of awkwardness fills him whenever he's with the two, he knows he should say something but has no idea what. "Oh, hey Armin/Mikasa, I was casually spying on you and overheard you planning to have sex with my adoptive sister/best friend. Wanna talk about that?" Yeah right.

Despite trying to avoid them, he can't help but keep an eye on them. He had no idea what he would do if he saw them sneak off; would he just let it happen or try and stop them. He's not opposed to them being together, he wants them to be happy, but the idea of them doing that bothers him.

To his immense relief, the two of them spend the rest of that day and all of the next, training like normal. They give no indication they are planning to sneak off, as they talk and exercise with the other cadets. Perhaps this 'opportunity' Mikasa spoke about isn't as soon as he feared. Good, that might give him time to work out what he's going to say to them.

Eren heads to bed that night tired, but relieved. During dinner, he had come up with the barebones of what he wants to tell them. He would tell them that he supports their relationship and that he was happy for them, but if either of them hurts the other, he will make the perpetrator wish the titans got them. Then he would follow it up with a group hug and then immediately begin teasing them as any good friend/brother should. He closes his eyes, content, and slowly drifts off to sleep.

He's not sure what exactly rouses him in the night, it's pitch black and mostly silent, yet something still disturbed his sleep. Drowsily, he looks around the dorm. He can see Bertholdt going through the motions of his bizarre sleep dance, arms and legs contorted in ways that didn't look natural or remotely comfortable.

Reiner and Connie are both snoring away, while Horseface mumbles nonsense in his sleep. Just a typical night in the dorms, so what the hell woke him up? He looks over to Armin's bed, and Eren is suddenly wide awake.

It's empty.

His mouth goes dry, "Maybe he's gone to the toilet? Yeah, that makes sense. He'll be back soon." So Eren waits.

And waits.

And waits.

Eren has been awake for hours when Armin finally returns. Even though the darkness Eren can see Armin looks completely exhausted, he walks as if he just ran hundreds of laps, dragging his feet along the wooden floor and ungracefully falls onto his bed with a 'thump'. Armin is asleep within seconds of his head touching the pillow, his soft snoring joining Reiner's and Connie's.

Eren spends the rest of the night staring at the wall, wishing for the dark void of the night to take him.

When his sister joins them at breakfast in the morning looking just as tired as Armin did, he wished that the ground would swallow him whole and end his suffering.