Disclaimer: I do not own Supernatural. If I did, Jo would have never died.
Flashback:
Sam sprung awake, looking at the wall with his eyes wide open. Something funny was going on. Suddenly, out of no where Sam sees Jo; but that was impossible, Jo was dead long ago. This couldn't be her ghost. Sam rubbed his eyes and went to look at where he thought he saw Jo, but instead the wall was blankly standing there. It was just another hallucination, mourning her death from long ago. A female voice was heard, "Hello? Can you two hear me. Earth to you two idiots?" Sam froze. That's Jo's voice… No. Not possible, he thought. Jo walked over to the wall Sam was staring at. "Is that a yes, you can hear me? Or are you just checking out that wall, because, you know, walls are sexy, too." Jo said, chuckling in between talking. Sam nodded, unable to reply, still feeling as if this were just a hallucination. Sam had conveniently let Dean stay at his place for the night- Dean sprawled across the floor. "D-dean. Wake up…" Sam got off the bed cautiously, not sure if somehow this wasn't Jo- just a demon in disguise, and shook Dean. Dean immediately woke up and moaned. "What." Dean managed to say, before rolling over on the floor and clinging to his legs. "Jo... Dean open your eyes. I think that's Jo, she's over there…" Sam pointed to the wall he last saw her, only to see she was gone. "Sammy, there's nothing there. Go back to sleep- it's three in the morning. Who knows, we might meet up with Crowley tomorrow. You need your sle-." The female voice interrupted Dean, a very familiar voice to Dean. "Shut up and listen to Sam, he's right. I'm here. Behind you two idiots." They both turned around, seeing Jo. Dean's face went blank, then quickly changed to one of stress. "No. It's impossible, Jo can't return. She's been long gone- I know she visited us as a ghost- but she would be evil now… And you don't look anything like a ghost." Dean stared at the figure looking like Jo; in complete disbelief. "Dean, I'm not a ghost. Certainly not evil either, I managed to plead enough to become an angel." Jo said, rolling her eyes at Dean. "You mean like Cas?" Dean said, a bit of disbelief still in his voice. "Who's Cas?" Jo said, sitting on Sam's bed. "Castiel. I'd assume you met him if you're an angel…" Dean said, the amount of disbelief in his voice increasing drastically. Suddenly Cas appeared in the bedroom doorway, and he leaned on it. "Ahem. I hear you're conversating, and I apparently am included?" Cas said, grinning slightly. Dean walked over to Cas, arms crossed, "Yes. Cas, meet… "Jo", she was killed and returned tonight as an angel. Have you met her?" Dean said, exaggerating on the air quotes around Jo. Cas looked past Dean into the room, seeing both Sam and Jo. Cas's eyes lit up immediately. "No, no, I have not… Though, Dean, she is an angel I can guarantee that." Cas said, now mumbling so Jo and Sam cannot hear, "and a very, very beautiful one, too." Dean suddenly got angered. He finally has Jo back, and now Cas wants her. This was his chance to have her as his own, and he can't just let it slip by.
End of flashback