Sitting at what was previously Sans's post was no fun at all for Papyrus.  He had been sure that Sans would continue his duties even after was kicked out of the house, but even if he had, papyrus was partially to blame there.  If his brother was not dead yet, somehow, he was not continuing his duties due to being replaced by Undyne.  She had replaced Sans without Papyrus' knowing, causing the chain of events that med to Papyrus sitting here now. 

The new recruit had been from the Capitol, and was looking for some more breathing room than the large city had to offer.  So Undyne saw that in her paperwork and then assigned him to Snowdin in Sans' place to see how he did.  The monster had even gotten to stay in the Rabbit's Inn for a month, if he had lived that long. 

Unfortunately for that monster, after Papyrus had gone to check Sans' station, definitely not to check for his brother, Papyrus had caught sight on the monster.  He had been wearing a black coat so similar to the short skeleton's coat that upon seeing him in his own coat, Papyrus dusted him without a thought. 

The only thing that was left was his coat, and Papyrus had run over to it as if his life depended on it.  The tall skeleton had gripped it tightly in his grasp, looking for some sign that it hadn't belonged to his brother. 

Which he got when he saw a photo of the monster with some other monsters and saw that the fur in the hood was a different color.  That and the jacket did not have Sans' name written on the inside of the right pocket, the golden zipper, and it lacked the smell of mustard and light smell of blood. 

Whoops.

So Undyne got pissed at Papyrus for dusting the new recruit and his punishment was to take his place until a new recruit was found, and be stripped of all other titles for a week.  So Papyrus was basically trying not to lose his mind and dust half the town at the moment. 

But in his mind, he was fighting an internal battle and losing.  He knew that love was a weakness that he was able to go on without for a long, but now he was struggling with the emotions he knew he shouldn't show.  He was pretty sure that he cared for his brother, even after all the pain Papyrus had caused him, even though it was a weakness.  He couldn't decide weather he cared or not. 

He had shown his emotions long ago, when he and Sans were children, but upon realizing that the underground saw it as a liable weakness, he quickly tried to shut them off to the world.  Unfortunately, part of the world included his brother. 

He had seen that Sans was suffering under his decision, but he figured that he could help to toughen up his brother, as to not have Sans be chewed up and spit back out by their heartless world.  However, now that he thought of it, his methods of 'training' had seemed to make everything worse. It had caused the shorter skeleton to become weaker and fearful of his own brother...  Heh, he probably didn't even care about Papyrus anymore... But he honestly couldn't blame him.

The vibration of his phone shocked him from his thoughts.  He could have mentally slapped himself for letting his guard down in public, and for so long too. The vibrations of his phone were the result of the alarm he had set for himself to remind himself that 'his' shift was over.  After gathering his thoughts and regaining his cold composure, he stalked off to his home.