His Witchy Mate

A girl destined to be a witch and a boy destined as a werewolf. Living near each other's city they fall in love with each other though they were prohibited to even cross paths with each other. 
Soon they decided to run away from their territory and live with each other but what caused the boy to not come?
Why did he leave her in the middle of their love journey? 
After some time, he came back as the alpha and the strongest and dangerous one out there. He wanted the girl now, but she didn't want him anymore.