"Dude, my soulmate is an astronaut"

Dramaaa
How about the next morning, the brothers meeting back for breakfast?

Sam raised his eyebrows when Dean collapsed down, and carefully slid the pancakes place to his side. "Morning?" He greeted him cautiously, surprised to see him that cranky after he had left him with a woman on the night before.

Sam was indeed dying with curiosity on his side. He let Dean the time to swallow down two pancakes and one coffee, before he cleared his throat. "Did things not go well with Janet?"

"Oh," Sam replied, a bit awkwardly. Then he cleared his throat. "Well, if you want to keep moving, I might have found us a case here, in Vegas, actually."

Sam followed Dean's gaze. "No, I figured he might still be sleeping, he replied automatically. He was a bit too focused right now on his big reveal, since he laid a hex bag on the breakfast table. "And here's our case."

"In the maid's troller," Sam answered. "Looks like somebody here does not like to lose their games, and is trying to get their money back somehow." He held back a joyless laugh. "I'll go get Cas, you should drink more coffee," he said, standing up to pat his brother's shoulder.

"...Well. eat light," Sam advised him, before he left the room.
He came back a quarter later, looking mildly confused. "So, uhm. Guess we're doing this without Cas."

"Still, I'd thought he would have warned us," replied Sam, frowning deeper. "I mean, he checked out of the room, and left no note, no text or voice message."

"I hope he won't make us wait too much this time," Sam sighed. "So. You ready to hunt that witch?"

The witch case went just fine. As well as all those other cases they solved in the next few months. Sam still made a point to trying to call Cas sometimes, even telling Dean that he was praying to him, but got no answer.
In the end, they found him when they expected it the least. They were investigating on odd stabbing deaths, when the sheriff they were about to question arched his brows.
"Oh, don't worry gentlemen, your colleague is here already, and got a look at the body. You didn't get in touch?"

Sam faked a laugh too, making a face to tell Dean silently that it was highly probably. "Do you happen to know where our colleague is staying?"
"Sure, at the motel down the road," the sheriff replied, as he opened his sandwich. "He's wearing a beige trench coat, y'can't miss him." On those words, he munched happily on his sandwich. "We good?"

Sam stood up, smiled politely at the sheriff, then lead Dean out of that room. "Think this might be Cas?" He whispered to him, a bit giddy at the thought they might have found him again.

Sam held back a huff, smiling with disbelief. "It's crazy. I mean he goes AWOL for several months, phone dead, and it appears he's not even in Heaven or anything?" He all but dived into the Impala, thinking hard over it.