I'm pretty sure Pokemon X and Y take place a long time after Red and Green, but correct me if I'm wrong.
"Oh what will I do without her?" The old man cried.
His wife had died the day before and all him Pokemon were also gone. His cancer was untreatable and only caused him pain. He felt so lonely. It was like living seemed no longer an option. He wanted to be with his wife and Pokemon once again. If only there was something.
The man picked up his medicine bottle. Ingesting half the pills would kill him instantly. Good-bye world, he thought to himself.
Suddenly, an odd youth ran in. the old man could tell this boy was a Pokemon trainer simply by looking at him.
"I'm sorry," Said the young trainer. "I heard this house was empty and that there was rare treasure inside. I must be mistaken."
"No," Replied the old man. "I still live here. But yes, I do have a single treasure."
He unlocked the glass cabinet and pulled out a small box. He opened it and showed the boy the Comet Shard inside.
"Amazing!" The trainer was mystified by the beautiful object. "Where did you get it?"
"I got it in the days of my youth, while I was visiting some friends in Hoen. I used to be a Pokemon trainer too, by the way."
"No way!"
The boy and the old man talked for hours about Pokemon, and the art of battling. They only stopped when they realized how late it was.
"Sorry we have to end it here." Said the boy. "My name's Xoan by the way, but everyone just calls me X."
"It was nice meeting you, X. Everyone calls Red." As X was about to leave the old man quickly spoke. "Would you be kind enough to give me a weak Poemon to keep me company? I promise I'll return it."
X gave Red his Bunnelby. He was planning on training it, but never got around to it and it just sat in his party. He didn't even have this experience share on.
He left after that, saying he'd one day return.
For days Red paid little attention to the Pokemon, but the little creature seemed to have fallen in love with him. It followed him wherever he went, and ever curled up in bed with him. Eventually the retired trainer started to feel the same way.
"You remind me of my old friend Pikachu." He said to the tiny Pokemon. "He was the only one I didn't release when I lost my position as champion. The poor thing lost its tail to a Frenzy Plant in that battle, and it was my fault, but that sweet Pokemon never left my side after that. Until it died last year."
The two were as close as could be, and that couldn't be changed. Until about a week later.
Red knew he was dying as he wrote the note, his Leukemia had caused him liver to cease function and it was useless to find a donor for someone off his age. He would no longer be able to care for Bunnelby and wanted it to be ready for X when he wanted to pick it up. He'd ever given it the Comet Shard. The letter read:
Dear X,
Your Bunnelby cheered me up so much. I wish I could've lasted longer, but it help me enjoy the end of my life. Thank you. I give you my Comet Shard, as it's no longer important to me. Take good care of this sweet Pokemon.
Sincerely, Red
He was found dead two days later.
X returned to the house on day and found the Pokeball and the note. After that he began to train Bunnelby, and it became his favorite Pokemon. He felt it was a sign of how important Pokemon are in the lives of the people around them.
If this gets enough popularity, I'll write a story about the creepy girl in Lumiose City.