A group of fresh college graduates get more than they bargained for when they go on a post-graduation camping trip. After accidentally stumbling into a cave, the friends find themselves in an undiscovered world with several tribes of 12-foot giants, not all of whom are happy to see them. As the friends return to their ordinary lives, they hope to leave the giants behind in their cave. But the realms of the giants and the humans are about to merge as the giants leave their home to explore. Driven by different motivations, the giant tribes unite against the humans. This, of course, means war. And in the center of it all are the only people who know the ways and language of the giants, those very same friends who have ventured inside the giants' caves. Intruders follows Clare, Gordon, Leo, Bryan, and Wendy—five ordinary friends who become embroiled in an epic battle against giants.
Zhen Lyu writes clever and resourceful women, as well as strong and ambitious men. Each has a unique skill that makes them valuable to the group as a whole, like Clare's ability to pick up on languages and Leo's useful inventions. The five heroes are not quite three-dimensional, but they are easy to root for and relate to. As the tension builds, the heroes become involved with the military, wriggle their way out of sticky situations, and learn how to deal with the giants—and their fellow human beings. Through their ordeals, the five learn what it means to be a good leader, whether the ends justify the means, and what true friendship truly means.