"Anybody home?' called Don as he walked through the front door of his brother's house. It had been a late night, an exhausting case and now he was looking forward to some down time with a beer and some company. Unfortunately, the only company that would realistically still be awake at this hour was his little genius brother.

Having one of the brightest minds on the planet wasn't always an advantage. Charlie sometimes suffered from acute insomnia, where his lightning-fast, ever-working brain refused to let him go to sleep. During those nights he would spend hours in the garage, furiously chalking away on various boards, complex patterns and mathematical equations whizzing through his head.

Despite their past differences, Don couldn't help but feel for his brother in those instances. Right now, however, he was kind of hoping that they could have a chat. They hadn't seen each other in at least a week.

He steered towards the garage and knocked on the door. No reply.

'Hey, Charlie, are you still up?' he asked, opening the door.

Sure enough, there Charlie was standing, with a furrowed brow and an expression of intense concentration on his face.

Just then, Don's phone started vibrating in his pocket, making a beeping sound.

Charlie was startled by the sudden noise, jumped and looked up. 'Oh, hey there, Don, didn't see you come in!'

'Yeah, hi, wait just one second, I need to get this.' Don made an apologetic face and turned to take the call.

'Eppes.'

It was Colby Granger, who sounded just as tired as he felt. 'Sorry Don, I know you just got back, but I'm afraid there's been another homicide. College student, 19 years old, completely different from the other victims, but same stabbing pattern.'

Don heaved a heartfelt sigh. 'Okay, thanks Colby, I'll be right there.'

Charlie had stopped his work and looked at his brother with an expectant expression on his face. 'Anything wrong?'

'I gotta go. That was Colby, there's been another murder. I'll see you tomorrow, okay?' He leant forward to give his brother a pat on the back and then turned to stride purposefully out the room.

'Don't forget to eat!' yelled Charlie as Don left.

'Yeah, yeah!' he retorted from the living room, having to grin despite himself. Don't forget to eat. Charlie was one to talk, once he was fixated on a problem, he could go without sleep or food for over 36 hours. He had seen him do it.

When Don arrived back at the Los Angeles FBI office, he felt a sense of both dread and déjà vu. He had literally just left this place for the night. He had hoped to not see it again until the morning. Add that to the fact that he was now dealing with the fourth murder victim in a month and it didn't look like things boded well.

Oh well, occupational hazard, he thought to himself as he got into the elevator. Another day, another dollar.

When he got out the elevator, he rolled up his sleeves and ruffled once, twice through his hair. Ready for anything the night might still throw at him.

Sinclair, Reeves and Granger were already gathered in the bull pen, which wasn't surprising as Charlie's house was the furthest away and it had taken him longest to get here.

Their faces were grim as he greeted them.

'Though I hate to say it, Don, I think we're going to need some additional help on this one' said Megan, turning her computer screen towards him to show him the new crime scene photos.

'Should I call Charlie and Amita?' he asked, looking intently at the blood spatters on the wall behind the dead girl. 'They could do that analysis thing that…'

'Not doubting your brother's skills here Don, but all we've got is four dead victims and no leads,' put in David. 'Megan had the idea that we could call in the BAU?'

'The BAU?' asked Don, slightly incredulously. 'But we already have an expert profiler!'

Megan nibbled the end of a pencil. 'That is true, but they are more highly trained, qualified and experienced than me. You've got to admit Don, we've got nothing. Just four apparently unconnected victims.'

'O-kay,' said Don slowly. 'I guess we could use the extra man power. This is going to require a lot of footwork, interviews, that kind of thing. I'll see what I can do.'

AN: So that was the first chapter. If you would like me to continue, please do drop me a quick review and let me know. Also, if you find spelling errors, typos, blindingly obvious mistakes or the like, do let me know! If you bear with me, I will introduce our two favourite teams to each other in the next chapter or so. Have a wonderful day, everybody, and thank you for taking the time to read.