Alpha!Dave and Dirk are long lost brothers who have never officially met. Dave ran away from home when he was younger to pursue a Hollywood career that his family thought was foolish--joke's on them considering he made it fucking big--but as a consequence he doesn't even know he has a little brother. Dirk, on the other hand, avidly follows any news about his brother and watches him from the shadows.
Their parents are long dead, killed by whatever organization recognized Dirk's talent and wanted to raise him into the assassin trade.
Crocker Industry loves young talent, after all.
Dirk kills targets and helps them develop new technology for their agents. They provide him with pretty much everything he could ever hope for and for an assassin he lives a fancy, lavish lifestyle. Of course, only if he obeys them without question. They can't use the mind control shit on him because he was the one that DESIGNED the mind control shit.
Then one day, Dirk gets a new target.
Until then he had only killed enemies of Crocker Industry and those who he could see posing a big problem. He doesn't understand how Dave can really be an issue, how can he be one of the bad guys? So he starts doing a little digging, both into Dave and into Crocker Industry. He finds out that the company he works for isn't exactly the company he thought. They have bigger plans, plans that Dave is subtly trying to ruin through his movies and fame.
Crocker Industry is trying to take over the world, Dave is leading a rebellion against them, and Dirk has been charged to take his life.
He tells himself that he'll do it, but after slipping up and actually talking to the brother he never had, it becomes harder and harder to actually take his life. He tries to get close enough to pull off the job but every time Dave will say or do something that has Dirk hesitating. And Crocker Industry is getting impatient.