The lone whistle

What happens when you're on another gangs territory; all alone.
The mark of Blood Rose before the kill someone is a lone whistle. What happens when Ariana hears that lone whistle in the dark of night. One note. Two people.
What happens when Ariana meets the head of Blood Rose.
Ariana knows that cliché getting sold to a gang leader but what happened when she gets traded by her oh so loving father.