Applejack paced through the corridor of Twilight's castle, trying to keep herself calm. For nearly a day Jack had been inside with Twilight, having all sorts of experiments done to him. Applejack didn't know what the tests were for. Twilight hadn't said anything. But she didn't need to. AJ had seen the look on Twilight's face back at the Crystal Empire. Worry, fear, but most of all, intrigue. Never a good sign with the princess. Applejack knew her too well.
It was going to be fine, she told herself. Jack was going to be fine. He hadn't survived all those battles with Aku, traveling across reality and surviving their daughters cooking just to be taken out here. He would be alright. He had to be. If not for his own sake, but for hers.
The sound of a door opening snapped AJ out of her thoughts. She turned her head to see Twilight and Jack walking towards them. She sighed in relief before running over to her husband, pressing her head against his neck before turning to look at Twilight. "So what's the news, doc? Is he gonna make it?" she joked.
Twilight's look told AJ this was not a laughing matter.
"Applejack, I'm not sure how to say this, but...Jack is perfectly fine. He's as healthy as he was twenty five years ago," Twilight said.
"Then what do ya look so morbid for? He's fine and that means..." AJ began, but Twilight held up a hoof to silence her friend.
"No Applejack, I mean he is EXACTLY as healthy as he was twenty five years ago. Because he's the same pony he was twenty five years ago. Physically at least," Twilight explained. "As in, he hasn't aged a day since the day you met him."
"What in tarnation are ya talking about? Yeah, Jack may look youthful, but that doesn't mean," Applejack began, turning to look at Jack. She looked into his face, certain that she would see some wrinkle or a little gray in his mane. But the closer she looked the more she started to realize the truth. There were no wrinkles. Not a speck of gray despite him being well into his forties. And just as Twilight had said, Jack looked identically to the day she met him...a day she would never forget.
"B-but that can't be...it has to be some sort of trick or..." AJ began. Jack raised a hoof and brushed it against her mane, before resting his hoof on the side of her face. Some strands of her own mane fell down in front of her face, allowing her to notice a few silver strands in her own mane.
"It is no trick, my beloved. I have not aged a day," Jack whispered softly. AJ moved closer and pressed herself against Jack, feeling him place a hoof on her back to pull her in tight.
"I've run all sorts of time tests on him. Running his body forward and backwards through time, temporal anomalies. Literally aging him up with spells---none of it works. Aside from growing a beard, his body didn't show any signs of change whatsoever," Twilight said. "It's like he's literally removed from time...like an alicorn."
"Do ya know how this might have happened?" AJ asked.
"There are a number of things that could have happened, but none of them could be from Equestria. If there were, my magic would have detected it," Twilight said. "There is only one other way this could have happened. Aku."
"He did this? Is it a curse? Some kind of prank? A last screw you to Jack?" AJ asked. "No, he hated Jack. What purpose would he gain from making him...well...immortal?"
"Not immortal. Time immune. There is a difference," Twilight said. "Jack can still be killed...I think...but he...he will...he will live pretty much forever so long as nopony kills him. I'm sorry."
"Why are ya acting so sad. That just means mah husband will be around long after me to look after are family," AJ replied, trying to brush it off. "That's a good thing. It means that-that ah won't ever have to worry about selling the farm. Or that Applebloom will have him to look after her. And also that...that..."
She stopped talking as Jack tightened his hug. Applejack couldn't decide how to feel about what she had learned. On one hoof, Jack would live forever. No pony was skilled enough to kill him and that was the only way he could die. He would always be around to protect their family, Equestria...but on the other, he would outlive her. She would die and Jack would live on. What would that do to him?
"I'll...give you two some alone time so you can talk about this," Twilight said, before leaving the hallway.
"Well that's one way to start a day. Still not as bad as the time we found out Sakura had inherited mah rainbow power," AJ said with a small laugh.
"I am so sorry my dear," Jack whispered.
"Oh will ya stop acting so sad fer me. Ah'm not dying, ah'm just getting old! That's not the same as dying!" AJ replied.
"That...is almost exactly what getting old is."
"Don't you use yer logic here, Jack, it won't work on me. This is not something we should be upset about. Yer essinetially an alicorn now. Yer gonna live a really long time, always being there to keep ponies safe," AJ replied. "So what if ah'll die before ya. Not like it's the worst thing in the world. Our daughter will never have to feel the pain of losing you. Or our grandfoals. Or any of our family. You'll always be there fer them. And who knows, one day ya might meet another mare that ya fall-"
"Never."
AJ snapped her head upwards to look at Jack, who was gazing down on her with a look that was a perfect mix of fury and love. "There will never be another that I will love as I have you. You, who saved me in so many ways, will for now and always be the only one for me! My only beloved."
"Uh...okay."
"I am sorry for my outburst," Jack whispered. He hung his head for a moment before looking Applejack in the eyes once more. But this time when she looked into his eyes, she saw the eyes of a pony who had lived for a long time. It was only thee second time she had seen this from him. "But you are my family. You are everything to me. If not for you, I would either be continuing my pointless pursuit into the past or dead at the hands of Aku. You gave me so much. A home, a family...happiness and then just imply that I will find another after you are gone. I will not...I cannot."
Jack pulled her tight again once more, his body shaking slightly. He was trying to stay strong. For her. But she knew him too well for that. He was scared. Not scared of the immortality or the years he would have to face. He was scared of losing her. Scared of having to live on without her. Applejack wished she could say something to comfort him, like how they would always be together or that they would find a way to overcome this. Maybe she could become an alicorn or find a spell that would keep her alive longer.
But she couldn't speak the words. AJ knew there was nothing she could say. Her time would come. It was the nature of the world. Even Alicorns and gods passed on eventually. Her grandfather had passed, her parents had passed and she too would pass. Even Jack, eventually. She didn't know how long it would take, but his time too would come. She just wished she could be there for him when it did.
So instead of saying anything, she simply returned his hug, drinking his in embrace, his warmth and his love. AJ knew she had many years left in her. But eventually her time would come. She couldn't add more years to her life. So she decided she would make sure the remaining ones were filled with as much love, laughs and good memories that she could fit.
And although she didn't say it aloud, a smile spread across her face at Jack's promise for her to be his only one. He was too good for her.