Written in the Sand: Book 1 of the "Written" duology

Mazikeen Sage ventured too far into an abandoned house, the hide locker being in one of the rooms up stairs, abandoned and alone. Her "friends" had dared her to go in there to see if it was haunted, alone. That's when she meets her hide, named Spitfire, known for being unpredictable, maternal, chaotic and bold. It chose her under the very unusual circumstances. After transforming for her first time, she finds out there are others like her.