You haven't expected any visits from Jack or his friends. In fact, it's been a few weeks since the last time you heard from Jack. That's how you know something must be wrong when he suddenly drops in for a visit. 

 It's around midnight when Jack shows up, and you're already asleep in bed. Thankfully, you're a very light sleeper, and you open your eyes when you hear him bump into your desk. You reach over towards the lamp on the bedside table, and switch it on. 

 "Jack?" You sit up in bed when you see him standing here. "What are you doing here this time of night? Did something happen?" 

 "Something did happen," he says. "I made something happen." 

 Jack has always been a little awkward, and at first you wonder if he's making this sound more dramatic than it actually is. 

 "Well, what happened?" you ask, rubbing your eyes. "What did you do?" 

 "I killed someone, Y/N. I...I killed Mary Winchester." 

 You pause. "Mary Winchester? Sam and Dean's mother? She's dead?"

 He nods. "I didn't mean to do it." 

 You sigh. "All right. Come here, sit down. What happened?" 

 "I swear it was an accident." He sits down on the edge of the bed. "I-I was having trouble controlling my powers. Mary was trying to help me, and I...didn't mean to kill her." 

 "Oh, Jack." You sigh again and take his hand in both of yours. "I know you loved Mary, and I know you wouldn't do something like that on purpose. Do Sam and Dean know what you did?" 

 He nods. "They do." 

 "I guess there's no reconciling with them, then?" 

 "How could I?" he says. "I killed their mother, Y/N. I don't think they'll ever trust me again. I don't know if I can even trust them now." 

 "What about Castiel?" you ask. "Maybe he would be more sympathetic?"

 He shrugs. "I don't know. Maybe. But I don't want to put him in the middle like that. It's not fair." 

 "All right. What are going to do next? Where are you going to go?" 

 "I don't know. But I think I should probably keep as much distance as possible from Sam and Dean, and maybe even Castiel. I just thought I might come visit you first." 

 "Oh. What made you think of me?" you ask. 

 He shrugs. "I don't know. I like you. You've been a really good friend." 

 You smile. "Thank you. And remember, you're welcome to drop in anytime, as long as it's not the middle of the night. Keep a better eye on the clock next time, Jack." 

 "I will. Thank you, Y/N. Hopefully, I'll see you soon." 

 He gets up, and flies away in a flash, and you're suddenly by yourself again. You turn off the lamp and get back into bed, wondering if Jack or the others will be needing any help in the near future.