Morphing is certainly more fun than Sega -- you can soar as an eagle and walk as a cat. But being an ANIMORPH is by no means just fun and games. Rachel knew better than anyone. One of her best friends, Melissa, is acting very strange. And it looks like Melissa's dad, who is also the school's Assistant Principal, may be connected to evil aliens. Rachel can't tell Melissa what the ANIMORPHS have learned, but Melissa doesn't seem interested in talking to Rachel these days anyway. Could Melissa be one of "them?" With the help of Jake, Cassie, Tobias and Marco, Rachel plans to enter her friend's house as a cat, intent on unlocking the secrets from within. If only Rachel could keep her mind off mice...