Arthur wanted to do something different to earn cash for the gang. A real job. One that didn't include shooting and killing folk all the time.

Catherine Braithwaite offered him a decent amount of money to take care of her adopted daughter without her last name, just to protect her and make sure she didn't get in trouble. So here he was in their manor, talking to Catherine. Then, he spotted someone in the corner of his eye, someone peering past the wall to listen to their conversation.