Book 1:

Oceana Daciana, who is promised to the Alpha of her parent's closest friend's son through an arranged marriage, realises her brother is her mate on her eighteenth birthday after eight years of his disappearance without a trace.
She was astounded by this finding, knowing that she had harboured these hot forbidden impulses for her brother since she was a child.
Oceana welcomes her brother, Gerard, home. But he doesn't want her and pushes her away from him, understanding the risk and implications of taking Oceana as his mate.
It is forbidden and a curse for them to be together.
He has to depart. He must find someone to take Oceana's position as his mate for the clan.