It was all his fault. That was the only thought rushing through James Potter's mind. On a terrible loop all he could hear beside the blood pounding through his years was a frantic and guilt ridden mantra of blame. He was supposed to have her back, on and off the battlefield, that's what being married meant, and he had let her down. She was laying on the hospital bed looking paler than he had ever seen, almost like one of the Hogwarts ghosts, because he had failed. It was all his fault.

Lily had been in Attack Team A, the first handful of Order Members who breached the perimeter first. He was on Team B; his task was to make sure she made it in safely. Usually Sirius would be on Team A alongside Lily, but he was off for that mission, instead staying at Godric's Hollow with three month old Harry. The Order had tracked a large gathering of Death Eaters to a small village on the outskirts of Edinburgh. There was no illusion that this would be an easy mission, Order intelligence had reported that some of Voldemort's top ranked Death Eaters, notably both Lestrange brothers, were using the targeted house as a base. Going into the battle every Order Member expected it to be fierce, the goal was to bring in one of the Death Eaters at the top of the hierarchy, dismantle the Edinburgh base, and collect any intelligence available at the location.

But the fight was more intense than expected. Nearly immediately the Order had to resort to defense tactics as opposed to the planned offense. They left with no intelligence, only the knowledge that there must be a spy in the Order, it is the only way the battle could have gone that terribly wrong. But spy or no spy, James was blaming himself. It was his fault. He was supposed to protect her and he had failed. Watching her get hit with that jet of green light made his heart stop.

For a split second he thought it was that shade of green. He thought it was the Killing Curse and she was gone. But it wasn't. It was a memory charm. At least that's what the St. Mungo's Healers told him. She was supposed to wake up soon but it was always hard to tell with memory charms or curses. So James was sitting alone in her all too sterile room, holding her all too limp hand, and staring at her all too pale skin. It was his fault. He should have protected her, stop the charm, have a shield up.

The quiet groan from the bed beside him woke James up in an instant. He had fallen asleep beside Lily as he waited for her to come to. Apparently the Healer's prediction of "soon" had been less precise than expected as five hours had passed since James was promised that his wife would wake. His limbs seemed to fly everywhere as he moved frantically to get closer to her. The momentum caused him to slip out of his chair and as Lily's eyes fluttered open, James was kneeling by her pillow, her hand clasped tightly in his.

As she came to, the first thing she said was not renowned or moving. She did not proclaim her love for her husband or curse the existence of Death Eaters. She barely said anything except a few groans and a barely audible, "Ow."

It seemed to take a lifetime to James until Lily was able to say more than murmurs. Her eyes fluttered open and closed occasionally for the better part of an hour. It seemed as if waking from her injury was an uphill battle. Yet, for as long as it took for Lily to wake once she began, James knelt at her side whispering words of love and encouragement. He could tell the exact moment that she actually pushed through the fog of her injury and could tell where she was. Her eyes came into focus and she tried to sit up.

"Hey, wow," James said, as she struggled up, "Stay laying down until the Healer is back. We really don't know the damages." He gently took her by the shoulders and helped her relax against the pillow again.

Despite shaking off his hands, Lily followed his instructions and lay back down, "What happened," She asked.

"The mission-" James began to explain, but he was almost immediately cut off by Lily.

"What did you do?" She continued, now with venom in her tone that James had not heard her direct towards him in years, "Why are you even here? Where's Sev?"

"Sev?" James repeated, concerned now not only about how she physically was but the damage done by the memory charm, "You mean Snape? He put you in here Lily. On the mission-"

Abruptly Lily sat up, it seemed as if she was going to lunge at James but instead she rested against the headboard in an upright position, too drained to do more. "That's absurd, Potter. Why would my best friend put me in the hospital wing?"

It took a moment to process what Lily said and as her words washed over him James found himself filled with dread. She referred to Severus Snape as her best friend. That hadn't happened since he called her a mudblood at the end of their fifth year. She referred to St. Mungo's as the hospital wing. Then James realized one of her earlier questions blamed him for putting her in the bed. Merlin, the memory charm was stronger than any of the Healers or Order members predicted. James ran a hand through his hair which had already been ravaged during his anxious wait for his wife to wake up.

"Lily," James asked slowly, "What's the last thing you remember?"

Her jaw seemed to go slack for a moment and her eyes unfocused, as if thinking back was impossible. She shut her eyes tightly before murmuring, "We just finished our OWLs I was at the lake… and then… you were… well I don't remember what you were doing but you threatened to hex me that I know and now I'm in the hospital wing so what did you do, Potter." Despite the confusion she had stuttered through, she ended her sentence with such disgust and hatred that James felt sick to his stomach.

James was about to reply when a Healer walked in. Running his hand through his hair again, James stood up and walked over to the Healer. Under his breath so that Lily could not hear, James began to explain what happened when she woke up. The conversation with the Healer was short and before he knew what was happening, he was being asked to leave the room and a small group of specialized Healers were entering the room.

"You're mad," Lily laughed, but not her usual lighthearted snort, instead it was angry and accusatory, saturated with disbelief, "The lot of you. There is no way I married Potter. There is no way I have a child with that self-righteous son of a flobberworm." She spat his name as if it had a foul taste and finished with a dark glare in his direction. As the healers came to understand Lily's condition and things were explained to her, Lily had become enraged. Eventually James had owled Marlene, Lily's best friend, to help her. Which had led to James sitting tense in the corner, staring at Lily as she argued about the fact that they were married.

For a split second Marlene gave James a sympathetic glance, before resuming telling Lily what had happened between the end of O.W.L.s and Lily being cursed into a St. Mungo's bed. James repeatedly had been running his hands through his hair. He knew for a fact that the last time he had been this stressed was when Lily was laying in the hospital bed, screaming in pain as Harry came into the world. However, that anxiety led to something amazing. This situation only made James dread the future.

A slight knock at the door caught the occupants' attention. They all turned to see a Healer. "Mr. Potter, if you could follow me," The middle-aged witch requested, "We have some important things to discuss about your wife's condition."

Nodding, James rose from his chair. He promised Lily he would be back shortly but she scoffed in response and told him not to bother. Fighting in a war, James had been under the Cruciatus curse multiple times but Lily's cold words hurt him more than all of those moments combined. Swallowing down the tears that threatened to fall, James followed the Healer into the hallway.

"Mr. Potter," The Healer said once they were outside Lily's room, "I have both good and bad news to tell you. The good news is we've been able to identify the curse used on your wife. It is a very powerful memory charm, Meminus Retro. The charm can only be cast by someone who knows the victim as it essentially resets the mind to a specific moment in their life, designated by the caster."

Force of habit caused James to run his hand through his hair again and he nodded. "Is that the good or the bad?"

"The good," The Healer said, "The bad is that, while the memories are still within your wife's mind, they are inaccessible unless triggered by a powerful emotional reaction."

"How powerful?"

The Healer smiled sadly, "Something life-changing. Something that would shock her back to the present, essentially. Do you know who cast the curse?"

James nodded again, "Severus Snape. A Death Eater. He was once Lily's best friend."

"Then the emotional reaction your wife needs must be the exact opposite of the emotion she felt towards her friend. It undoes the curse, in essence."

"What happens if we can't trigger her memories?"

"Then she'll spend the rest of her life without her missing memories."

"Fuck," James snapped, slamming his fist against the wall. He had no earthly idea how to trigger her memories. He did not know if he even had the power to trigger such an emotional response. Standing in the hallway as the Healer's words resonated in his head, James was certain his wife would never remember any of the good moments in their relationship. She was essentially lost to him.

It had been an hour since Marlene had left and the hospital room was silent. James was lost in his thoughts, the fear of Lily never loving him again seeming all too real. Lily was refusing to even look at James, much less hold a conversation with him. James, always being a person with too much energy, kept bouncing his leg as if the motion was removing the anxiety from his body. He was certain that this was going to be the rest of his life, cold silences, resentment, and tense air between him and Lily. That is assuming she does not demand a divorce. Merlin, James hopes she will not demand a divorce.

James self-deprecating thoughts were cut short by the sound of a baby crying. Attuned to listening for Harry at all times, James's head shot up. He found the source of the noise was indeed his son. Sirius was down the hall, making his way to the room with a fussy Harry in his arms. Glancing at Lily, James saw that she was still turned fully away from him, her expression angry, and her eyes trained to the floor. Sighing, James left the room to stop Sirius from coming in and aggravating Lily even more.

The best friends met each other just outside of Lily's room, visible clearly from the window in the room. Despite the terrible situation, James could not help but smile a little as Sirius shifted Harry into his arms. A few soft bounces and hushed words soothed Harry's tears and soon the baby was curled up in his father's arms, asleep. Hearing the baby's cries, Lily could not help but turn to the window. She watched in awe as James took a bundled up baby in his arms and pressed kisses against familiar dark unruly hair. She could not hear any of the exchange between Sirius and James, but Lily could not tear her eyes away from the window.

"How's she doing, mate?" Sirius asked once James was finished calming Harry.

"Probably better than I am," James sighed.

Sirius shook his head slightly, "I'm not so sure about that. I mean, imagine fifth year you waking up to a child and being married to Evans."

"I would have been ecstatic and you know it."

"Yeah, Prongs, but you also would have been terrified out of your mind."

James shrugged sadly, "I am right now." He glanced down at Harry, for the first time since the failed mission feeling alright, just at the sight of his son. But then his son stirred, for a moment his eyes fluttered open, the same brilliant green as his mother's, before he fell back asleep. It was in that split second, where James stared at his son's stunning eyes, so reflective of his mother, a mother who might never remember him, that James broke down. It was as if he was hit with a tidal wave of emotions. All of his fears of the day were suddenly being released. His arm not holding Harry reached out and he clung to Sirius. Sobs wracked James's body as he realized his wife might never love him or their son again.

She had not meant to watch James with Sirius. It wasn't her fault that the blinds to her room were open. But what she saw shook her. James Potter clearly was no longer the arrogant toerag she remembered him as. He was breaking down in the middle of a hospital hallway because of how much he cared for her. Wrapped tightly in his arms was a child, one that he clearly loved desperately. He was clinging to his best friend like the world was knocked out from under him, all because he thought he lost her. The realization washed over her, making her gasp. James Potter actually loved her. And for him to react so tragically to her injury, she must have loved him in return. Merlin. She loved James Potter.

For a split second Lily thought her heart stopped, once she realized that despite her past, her current self was in love with James. Then, as soon as the thought hit her, a flash of green light filled her vision. As the light faded, she was hit with a rush of memories. She remembered. Loving James had changed her life before and realizing that was enough to bring back her memories.

James and Sirius saw the flash of light emanate from Lily's room. Both immediately burst through the door. With Harry still asleep in his arms, James hurried to Lily's bedside.

"Lily?" The desperation seeped through his words, "Are you alright?"

A smile spread across Lily's face and in response she reached up and pulled James to her, kissing him soundly on the lips before pulling Harry from his arms and peppering kisses across her son's face. James stared at her gob smacked, not expected her actions. In response she smirked at him and asked, "Don't you mean 'alright, Evans'?"

In an instant an ecstatic grin spread across James's face, matching the one on Lily's, "You remember." He said.

"I remember," Lily confirmed, taking his hand, "And I love you."

"Merlin," James sighed, sitting beside her on the bed, "Don't you ever scare me like that again."

A/N:

Memini: (Latin) Remember

Retro: (Latin) Back adv.

I'm not ecstatic with how this fic turned out but I did really want to post it because I'm never satisfied with the number of Jily memory loss fics, I love the trope and I am desperate for more of them.