A Hidden Enemy

A Hidden Enemy is the second book in the Survivors series, written under the name Erin Hunter and published in 2013, and it continues the story of Lucky and the dogs who survived the earthquake.

Lucky and the Leashed Dogs have been looking for a place to live since the disaster that emptied the city, and the forest they discover appears to be the answer: there is prey, there is fresh water and there is shelter. The problem is that a pack of wild dogs already holds the territory, and their Alpha has no intention of allowing newcomers to settle on it. That leaves Lucky, who has spent his life as a lone dog and knows how to move without being noticed, working behind the other pack's lines to find out what they intend and whether an arrangement is possible. His difficulty is that he understands both groups, which means that whichever side he chooses he will be betraying dogs he has come to know, and the series keeps its conflicts personal even when the stakes are a matter of who lives through the winter.

The Survivors novels are told from the dogs' point of view and give their packs laws and rivalries of their own, and this volume is where the question of loyalty becomes explicit.