Maintaining interest in a story line that transpires over a series of novels is chal lenging. One good way to do it is with foreshadowing, but Applegate is faced with the challenge of dropping the tantalizing phrases of mysteries to be solved and action to come without compromising her fictional narrator, April. So, the author does this in part by having characters mention their plans or worries in vague terms, for example, Merlin shows himself to be actively involved in the contest for possession of Senna without giving away exactly what he means to do with her. That he is an enemy of Loki does not mean that he is a friend to April or to earth, although he drops hints about wanting to protect Earth.

Cryptic remarks by characters is another way to foreshadow future events and whet the audience's appetite for more adventures in...