I don't own Supernatural and never will. No copyright infringement intended.
Once Charlie and Dorothy began to pine for home, they decided to take a trip back home. Charlie missed Sam and Dean and wanted to see what they were up to. Plus, she wanted to officially introduce Dorothy as her girlfriend. She hoped they'd be excited to see them.
The portal opened, and the two women stepped through, hand in hand. Dean and Sam were nowhere in sight, but that didn't surprise Charlie. They were probably doing something important and hadn't noticed anything weird going on.
So both women walked through the bunker calling their names (not even thinking about the boys possibly being on a hunt) and were rewarded with an answer about ten minutes later. "Charlie! Dorothy! When'd you get here?" Dean grinned at them both.
"Just a few minutes ago. Did you not hear us before?" Dorothy smiled back.
"Sorry, this place is fucking huge. Sam heard you first and went to look in the opposite direction. I should probably call him, but he'll make his way back to the library. Come over here, Charlie." He held his arms out and a beaming Charlie went in for a hug. They enveloped each other for a few minutes before pulling away from one another.
"Let's go to the library now." Dorothy started walking and Dean and Charlie followed her. Dorothy and Charlie sat down next to each other and linked their hands together under the table. Sam joined the three of them fifteen minutes later and ended up hugging Charlie too.
"I'm glad to see you, but what made you decide to come back?" Sam questioned.
"Well, we missed it. Actually, I mostly missed home and wanted to come back for a visit. Dorothy and I aren't sure how long we're staying, but we are definitely going back." She loved Oz and wanted to go back. Plus, Dorothy had promised they could take the red brick red, even though it promised a lot of fucked up things. It was still an adventure at least and maybe they'd get to tell even more awesome stories. She was sure Sam and Dean would appreciate them.
"And I couldn't say no to her." Plus, Charlie was irresistible, thus it was no wonder she gave in to her girlfriend most of the time.
Sam watched their interactions for the next hour and a half, wondering if they were together. His suspicions were proved when Charlie and Dorothy sneaked in a kiss when they thought no one was paying attention. He smiled and went back to watching the movie. He eventually got tired and went to bed. Dorothy was exhausted herself and headed towards another bedroom less than ten minutes after that.
Charlie watched Dean putter around and decided to go ahead and tell him about her relationship with Dorothy. She didn't think he'd be upset or anything, but she wanted him to be excited for her. He noticed she was staring and stopped what he was doing. "What?"
"Dorothy and I are having fun in Oz. Aside from the flying monkeys. Those things are fucking terrifying. Anyway, we're together now."
He wasn't surprised – Dean had noticed how close they were tonight. "I know. Are you happy?"
She nodded. "Yes. I haven't been this happy in a long time."
"You love her?" Dean didn't want her to get hurt and was thus a little overprotective of Charlie. Sue him.
A smile crept up on her face. "Yeah. I make sure to tell her whenever I get the chance. She doesn't really like mushy feelings, but I still tell her."
"She love you?"
"Yeah. She actually said it first, you know? She actually caught me off guard. I really wasn't expecting her to tell me after we escaped from attacking flying monkeys."
"Then as long as you're happy, I'm happy. That matters, Charlie. You got yourself a kickass woman." He hugged her again, and the two went off to the kitchen to find something to eat because both were starving.
Charlie slipped into bed after she and Dean tore into some pie (she was surprised he actually shared). Dorothy stirred. "You finally exhausted yourself?"
"Yup. I love you so much, Dor. Just wanted to let you know." Charlie kissed and closed her eyes, ready to sleep in a nice, warm bed for the rest of the night.
Dorothy kissed her back and Charlie shifted for a few seconds, but settled down.
Dean ended up walking Charlie down the aisle a year later when the two women returned from Oz again and decided to marry. Castiel ordained himself online and married Charlie and Dorothy, while Kevin and Sam stood in as best men. Everyone agreed it was a beautiful wedding and Dean always denied that he cried during the ceremony.
There really was no place like home, and they were grateful they had a family that loved them this much.