Addiction by Blandine P. Martin

After losing her mother, Joe receives a letter revealing the name of her biological father and where to find him. Lonely and helpless, the young nurse decides to pack it all in to look for her estranged father, Jerry Welsh, who owns a bar and runs a motorcycle club in California.
Surprised to learn he has a 27-year-old daughter, Jerry still agrees to give her chance, and he welcomes her into his inner-circle, including his family. Soon, Joe uncovers the true nature of the club. Besides being passionate about motorbikes, these men are members of a gang controlling all sorts of underground activities.
Now Joe is about to step into a world that leaves no one unscathed.