 The fourth book in the series was covered in the episode "The Message".The TV episodes did not follow the books faithfully, altering many aspects of the characters' roles within the Animorphs, the events in the war against the Yeerks, and added plot lines that were not present in the books.A review in School Library Journal calls the book "average series fare" with "stock characters", although the reviewer did praise the descriptions of animals and called Cassie's personal struggles realistic.