"That's my sister Mary. She was really happy in San Francisco. After her accident, she made some new friends. 'Til we moved. I'm kind of worried about her…it's not like her to be uncaring." Allison's older-sister Mary is a werewolf. She's kept it secret, and becomes a secret weapon against the Kanima. As part of Derek's pack, she's the fierce mama-wolf.

Imagine how the story of our favorite werewolf would change if Stiles had a twin sister? And what if she falls for the mysterious lone wolf Derek? Derek/OC, slight Derek/OC/Isaac love triangle & Scott/Allison Warning: This is going to be a slow burn!