A Gang, A Love, & A Death (A Severus Snape love story)

Katarina is a normal witch. If you consider being a Califonian street fighter and gang leader normal. She does. She considers punching the daylights out of people and shooting someone all in a days work. Her gang, though, is different. They are all magical. Not all are witches and wizards, but they are all magical. So, when the Ministry of Magic catch Katarina at one of her fights, they are quick to arrest her and send her away to Britain. To teach. But what if thats not the only thing happening? What if Katarina is falling for someone, even though she has indestructable walls high around her heart, as cold and dangerous as her?