Animal Kingdom by Ashley L.

Six months after a devastating attack that turned her into a werewolf and left her brother in a coma, Serena Carlyle is barely holding it together. She thinks she's finally caught a break though when she literally runs into another werewolf named Leo on the full moon. Unfortunately when someone confesses to attacking her, she realizes there's much more to the night she became a werewolf than she originally thought. With Leo's help, she starts to dig into the mystery surrounding that night with only a few cryptic clues to guide her.