The Ninth Circle: World on Fire - Side Jobs, Book 1 (Unabridged‪)‬

Arthur Vangeest has been hunting a cult known as the Ninth Circle for months and finally located their base of operations, but something goes terribly wrong before he can strike at them. Someone he trusts betrays him, and his wife and young daughter are murdered. Now he isn't sure if there is anything left to live for. But, when he exacts his revenge on the people that hurt him, he finds a new reason to stay alive.

This short story takes place several years before the events of Raven's Peak and details when Arthur first discovered Abigail and how she gave him something new to live for.