Jem was born into nobility and good, easy life, in a village the dogs living there called Cresthill. She had servants to hunt for her, groom her fur and bring her anything she ever could've asked for. She was naive and didn't wish evil, but thought everyone's deepest desire was to serve her.
Her life changed drastically when Cresthill got attacked by another pack, and she had to leave.

Jem never really adjusted to living in the wild and fending for herself. Just as she and the few remaining cresthillians were starting to build a new life in a small abandoned mill, that too was invaded by a stronger pack, and Jem ended up alone, hungry, cold and in the end... dead.