The Wolf's Lullaby

I would suggest that you read and find out, but here is the description:

Millie Miller is 'The Wolf'-and no, she's not a werewolf. She's something much more dangerous: a shadow in the corporate underworld, a woman who built an empire out of cold steel and calculated silence. She doesn't have a life; she has a career. She doesn't have a heart; she has a mission.

Then she met Billie.

Millie found herself breaking her own rules. No more distance. No more indifference.

This is the story of how a predator learned to protect, and how a girl with a song in her heart taught a wolf how to love.

The Vibe: Protective/Powerful Female Lead, Hurt/Comfort, Found Family.