The King's Fire - The Dragon Ruby Series, #2

The monent Aithne's mother told her that her sister had been captured by the infamous Vamire King Lazzaro -- she should have known it was a trap. In order to get her sister back, she is given one simple, but dangerous task. She has to capture a dragon-shifter and bring him back to the King. It should be an easy, simple exchange -- her sister's life for that of a dragon. Nothing is ever what it seems and soons she finds herself drawn to the very people that she may be forced to betray. As King of hte Dragons, Viktor's one true goal is to keep his people safe.
His old friend Chase has become the first dragon-shifter in centuries to find his mate. His people are finally starting to have hope that balance can be restored with the newfound Earth Witch sisters. Keeping them close, he finds himself intrigued when they begin a friendship with a beautiful and mysterious new redhead.