Alex knew from first sight that Ice wasn't going to be just a friend. The two were closer than normal friends would be. Spending nights at his house, going everywhere together. But there was something Alex never knew about her.
Ice knew from the moment she was older that her and Alex's souls were entwined. And that keeping her identify secret as a Snow Woman would be impossible. And the fact that she is a exile from where she came from. But she knew Alex was meant for her even before he did.
On his sixteenth birthday was when Alex discovered she was his mate. And they sealed their bond as soon as possible. But the past can't stay buried forever and Alex will have to fight to keep his mate safe.
So this takes place in the future so there will be new characters you haven't heard about. Isaac will be older, Isadora will be older. The Immortals series will be over during this book, not literally, but the conflict will be solved in here. There won't be major spoilers, but still some. So do beware.
Book 8 of Entwined Mates, can be read as a standalone.