A/N: Hey! I hope everyone is well. A while ago, I mentioned in Partners Until The End' that I would start a multi-chapter fic dealing with a Maggie/OA relationship and the events of 4x18. That note was in the chapter titled 'By His Side' which is a one-shot set after 4x18 with the two of them as just friends. I wanted to keep the title in this one similar so that they are like companion pieces in a way. This will probably be a long one, and is definitely heavy on the Zibell ship, so you've been warned if you're not a fan of that. Anyways, I hope you enjoy, and please let me know what you think!

…

This was hell. That was the only way OA knew to describe the world in which he currently found himself.

As he made his way to room 481, he barely remembered performing the simple task of putting on his FBI hoodie and sweatpants. All he could focus on was the news Jubal had given him just moments ago.

The ASAC made it clear that Maggie's condition was still unknown. Her exposure was so severe that they didn't know how or if her body would even recover… and that terrified OA beyond belief.

He had been waiting in his own hospital bed for what seemed like hours before Jubal came in… all that time spent agonizing over the unknown and what ifs.

Now, he was finally able to go see her and he had no idea what to expect, so with his hands in his pockets and his heart in his throat, he cautiously made the trek to the agents gathered outside his girlfriend's door.

Jubal had rejoined the small group, anxiously snapping at the black band that had taken up residence on his wrist, and Scola and Tiff were standing in the back, both silent and wearing similar grim expressions.

Then there was Isobel, her face blank, the SAC showing no signs of emotion… and OA had to swallow the rage that washed over him upon seeing the woman.

She was responsible for this. She was the reason Maggie had been in that lab without protection because she didn't allow them to wait for SWAT… the reason why Maggie was currently lying in a hospital bed fighting for her life.

OA had never wanted to go off on someone so badly… but he at least had half a mind to realize that doing so would most likely result in him getting kicked out of the hospital, and there was no way he could let that happen. Instead, with his iciest glare directed towards his boss, he squared his shoulders and asked if they had heard anything else.

"The doctor is hopeful." Isobel didn't elaborate, but OA needed more than that.

"What the hell is that supposed to mean?" He couldn't help the harshness of his tone.

"He said there's a reasonable chance that she will make a full recovery."

OA mumbled to himself, "Good chance." That didn't sound too hopeful to him. Knowing his own chances of losing it out in the hallway were pretty high, he pushed past Isobel and the others, ignoring the window into Maggie's room and heading straight for the door.

He hesitated for a moment with his hand on the door handle, afraid of what he would find on the other side… but then, not being able to stand another minute away from Maggie, he gave himself a resolute nod and pushed open the door.

Looking up, he let out a sigh, his eyes immediately stinging with tears. Maggie was unconscious in the bed, the hospital gown and blankets swallowing her small frame. She was hooked up to various monitors and machines, including a nasal cannula, and OA's heart broke all over again.

He closed the door behind him, then stepped further into the dim room, again focusing his complete attention on her. She was so still, the only movement coming from the slight rise and fall of her chest. At least she was breathing on her own, though with the help of some extra oxygen.

The room was quiet, except for the steady beeping coming from Maggie's heart monitor, and OA took a moment to let that sound wash over him. That sound was a comfort… it meant she was still alive, still fighting.

OA moved so that he was standing directly beside of her bed, then reached down to lift her small hand into his. It was warm, and he rubbed his thumb over the back of it. "Hey, Mags… it's OA. I don't know if you can hear me… the doctor said you just need to get some rest and then you can come home and back to work… because I need you to do that."

He squeezed her hand, and though he really didn't know if she could hear anything he was saying, he desperately hoped she could and continued to pour his heart out to her. "You're not checking out on me, I'm not going to allow it. Do you understand me?" He was trying to hold back the tears, but was fighting a losing battle.

His voice raw and strained, he continued to tightly grip Maggie's hand like his life depended on it. He took a deep breath, hoping to get everything out before he completely fell apart. "Do you understand me, I'm here and I'm going to be here for you, for as long as it takes, okay? I need you… I need you. I can't do this without you, I don't want to do this without you."

He meant every word he was saying, every bit of it was the truth. He wasn't just talking about the job either, he was talking about life, about everything. He didn't want to do anything without her by his side… and he honestly didn't know if he could, not after everything they had been through together.

"I need you, Maggie… I love you." As he stood there staring at her features, he was taken aback when she nodded. At first he was pretty sure he imagined it, but then he knew, he just knew, that she had heard every word… and it overwhelmed him with the most relief he had experienced all day. "There she is. It's going to be okay."

He hoped with everything in him that those words were true… but after what Maggie had just been exposed to, he couldn't be so sure.

OA grabbed the chair behind him and pulled it as close to Maggie's bed as he could get it. He sat down and reclaimed his hold on her hand. He reached up with his other hand and tucked a strand of her dark hair behind her ear. She was still beautiful, even after everything that had happened that day.

How had it come to this? Going into their case, OA imagined and feared what he thought was every possible scenario, every possible thing that could go wrong… and while something happening to Maggie was always on that list, he never could've imagined this.

The whole time, he had to face his fear of a sarin gas attack, but truthfully, he realized that wasn't his biggest fear anymore…

It was losing his partner.