A.n

Cassie is bestfriends with the one and only Scott Mccall, and Stiles Stilinski. Stiles knows about Scott being a werewolf but cassie doesn't know and they don't plan to tell her.
It would simply put her in to much danger.

When Scott starts acting weird, she goes full out detective. she realizes he talks to Derek a lot. so that's where she is going to go.