Cage

For the past two years, Aphrodite and her adopted family have lived peaceful lives among the humans (more or less). They've made new friends, new relationships, and even graduated from high school; but nothing can make them forget that they are not humans themselves.
Aphrodite continues to struggle with her true identity as a morpher: an animal who can change into a human at will—which is a difficult secret to keep even without being a Dreamer anymore.
Apollo, now in college, faces similar challenges while also feeling increasingly anxious about Aphrodite's lack of Dreams. He and the rest of the morphers have bigger problems on their hands, however, when Aphrodite is captured by someone they know...

This book is the second in an ongoing trilogy.