Vow of Obedience by Brianna Hale

Don’t cry, little girl. Daddy will forgive you.
The job was meant to be impossible, even for the Cavalieri Della Morte. Kill Adelmo Lange, the reclusive crime boss who murdered my brother.
Until her. Adelmo’s daughter.
Branwen has taken a vow of silence to atone for her sins, but I don’t need her to say a word. She’s the bait that’s going to draw my target out.
Now she’s going to swear another vow. A vow of obedience. To me.
Together, we’re going to take down her father. If she does exactly what I tell her, she may even escape with her life.
Do as daddy says.