Cass sighed heavily and sat back down in his chair, folding his hands in his lap. He knew it would be pointless to go after Dean, so he would just wait patiently until Dean reemerged.
Meanwhile, Dean was pacing in his bedroom, clutching his forearm where he had been branded with the Mark. A hot, searing pain had ripped through Dean after he acted out towards Cass, and Dean tried to get a grip of himself. He knew he had better control of this violent and demon side of him, and, sure enough, Dean found himself breathing evenly once again, his mind completely clear and his body calm within just several minutes. Unfortunately, there was really nothing for Dean to do in his destroyed room, but knew that if he went back to researching, Cass would still be there. Dean decided he would just stay put, but the pure boredom of staring at a wall drove Dean to finally leave and go back to the foyer of the Bunker.
Like Dean had predicted, Cass was sitting down at the table. He hadn't even moved slightly since having sat down. Dean sighed and walked closer towards Cass, who didn't even raise his head to look at Dean, but instead continued to stare straight ahead.
"Look, Cass, about that -", Dean started, but Cass cut him off.
"It is fine, Dean. I'm sorry I can't do anything. But I will keep trying." And, with that, Cass vanished, leaving behind only a slight wind that rustled some papers on the table.
"Damn it," Dean swore, mentally cursing himself. Dean pinched the bridge of his nose, took a deep breath, and sat down exactly where Cass had just been, and opened another book.
The next several days were ordinary, and actually were considered normal in Dean's mind. He spent his days researching nonstop, and would occasionally be joined by Cass who would pop in now and again, telling Dean of his most recent lead or a rumor he heard about how to cure him. However, none of Cass' or Dean's research has been fruitful, but still Dean enjoyed the company. Sometimes Dean would even allow themselves to take a break from studying and started introducing Cass to Game of Thrones, Star Wars, and Doctor Sexy M.D. It was much more entertaining to watch the shows with Cass now that he was 'pop culture savvy'. However, it also meant that Cass knew the ending to every season of Game of Thrones so Dean could never be surprised. Cass would then make himself and Dean peanut butter and jelly sandwiches, as per Cass' requests, and they would both laugh over the fact that they could eat them but couldn't taste anything, as if that were the funniest thing in the world and as if nothing else mattered. These were the days Dean would remember and cherish the most. He finally felt as if he got his best friend back, and Cass would sometimes even forget that he was essentially watching TV with a demon. And when Cass would remember, he just pushed that thought off to the side because it was the first time in a long while that Dean seemed actually happy, and he was happy with him. Even Cass had to admit that Dean had taken what seemed like complete control over the Mark and his anger, and for the time being, everything seemed perfect. It was, in fact, until Dean decided to return Sam's call that Sam had left saying that everything was fine. Dean had called several hours later, and no one picked up, despite having called all of Sam's cell phones. And when Dean called a day later, the answering machine said that the number was disconnected. Sam never missed a call from Dean, so Dean eventually had to think the worst. Sam was in trouble.