You can never be mine

Samuel is a white magical wolf. He had been sent to watch over Katrina and protect her from evil. Nowthat she found her mate, he can go back to his realm. Yet he soon starts to notice a scent on Katrina that excites him. One day he investigates and finds his mate. How can she be human, if he is not? He knows he will need to leave their world soon.Cali was walking home one night when a white wolf approached her. She visited him every night after that. He asked her not to tell anyone. She will shift for the first time in one more day. If he can never be human, she will stay a wolf forever, if it means being with Samuel.Will Samuel join evil so he can stay or will he leave forever?