Being an assassin is the hard thing you do right now, because it was your job. You're an orphan who lives in orphanage until someone adopt you when you're 15. But now they're not your stepfamily because they only see you as a tool. Since you were 16, they keep training you how to fight.

Eventually in one of the missions, you meet Ace, your only friend while in the orphanage. But you met as enemies, not friends.

"Yuuta, is that you?"

He asking with a trembling voice, he's frozen in place. Unable to move because of shock.