A life after the death of your loved ones is not really easy.
Cira, the chosen Luna of the next Alpha, married him because of love, but everything was just a set-up for the Alpha.
To be able to get the position, he was forced to marry the chosen Luna, and having the authority to rule the pack can help him investigate his mother's death.
Their wedding was a disaster. The Alpha left to avenge after the death of almost half of the pack, and Cira was left with the pack, who hates her for being a brat and war freak before.
The tragedy turned Cira's life upside down, especially after the Alpha came back and started showing grudge against her.