AU after 5x01, when Dean says that he can't trust Sam, Gabriel comes to help Sam to take Lucifer down and Sam accepts his offer and goes with the archangel to train to kill Lucifer/
Dean couldn't trust Sam after what happened. They both drove silently towards the motel and the only sound was sam's sniffles and Dean felt a little bad for his brother because he didn't knew that killing Lillith would release Lucifer, whatever Sam was doing was for revenge against what happened to his brother. Now Dean felt guilty of what he said to Sam at the hospital. When they reached the motel, Dean was about to start a conversation when Sam walked out of the car and closed the door of the car with a thud and Dean winced at the anger and hurt.
Dean carried their bags into their room and he saw Sam going to the bathroom. Dean contemplated whether to talk to his brother or not. After a few minutes, Sam walked out of the bathroom and past where his brother was standing in the room. Dean watched as his brother went to bed and turned his head away from Dean because Sam couldn't look Dean in the eye after everything that had happened.
Late in the night, a fluttering of wings woke the brothers up. They thought it would be Castiel but it was the trickster of all people. "Hellllloooo boys" the trickster said and both were ready to shoot the trickster if he does something. "Woah woah woah, I come in peace" he said raising his hands up and both put their guns down. "Why are you here, Loki?" Sam asked. "Okay, so enough with the fake name, let's move to the real one" he said and both were confused. "What do you mean?" Dean asked. "Alright, let me introduce myself. Hi, I am Gabriel, archangel of the lord" Gabriel said and showed his wings and both Sam and Dean were astonished. "You are THE Gabriel?" Sam asked. "Oh come on, Sam, no need to go all fanboy on me" Gabriel said.
"Why are you here?" Dean asked. "Well, to help ofcourse" Gabriel said. "Help? Why?" Sam asked. "To defeat Lucifer. I hate him as much as everyone and therefore I can tell you a way to defeat Lucifer" Gabriel said. "And how is that gonna be possible?" Dean asked. "By sam's powers" Gabriel said and both were shocked. "No way, Sam is not using his powers again" Dean said. "Not the demonic ones, dumbass. The Angelic ones" Gabriel said. "Angelic ones?" Sam asked. "Yes, so let me tell you what really happened on November 2nd 1983" Gabriel said and both Sam and Dean nodded. "When Azazel came in Sam's room and fed him demon blood, me and Dad watched all of this and after your mother burned, and you three went to a motel to sleep for the night, John went outside to meet someone. That's when I came in the room and looked at little Sammy and you Dean-o sleeping soundly. My Dad had said to give Sam some of my grace so I came into your room and gave some of my grace to baby Sammy. Now it's time to use that" Gabriel said and both Dean and Sam were stunned by the revelation that Sam had archangel grace in him. "So, Sam, are you ready to take on Lucifer?" Gabriel asked and Dean looked at Sam, hoping that Sam would say no because Dean didn't trust this guy.
"Sammy" Dean said and for the first time in hours, Sam looked his brother in the eye. "Well, Sam?" Gabe said and Sam looked at him. "Alright, I'll do it" Sam said and Gabriel smiled while Dean frowned. "Sam, what are you thinking? I don't trust this guy. What if something happens?" Dean asked. "It's not like you trust me anyway" Sam whispered and it felt like Dean had been punched in the gut. "Let's go" Gabriel said and Snapped hid fingers and Sam and the archangel weren't in the room anymore. "No, Sam" Dean whispered and was left alone in the room.
Author's note: My new story. Hope you guys like it :)