In springfield, Illinois, ordinary iguanas have become invisible ...and they're huge!

Alyssa Barryton has been asked to take care of her friend's iguanas while he is on vacation. After all, Alyssa has her own iguana, and she knows how to take care of them.

But something goes wrong, and it's not long before Alyssa and Ryan are faced with a huge problem: a problem that's bigger than they are . . . and invisible!

Now, it's up to both of them to try and stop the unseen creatures before they create destruction and chaos across the entire city of Springfield!