TWILIGHT (Warriors: The New Prophecy, Book 5)

Before there is peace, blood will spill blood…
New territory brings new troubles for the fierce cats of the warrior Clans, who are still uncovering the secrets of their new home around the lake. Dangers they have never faced before are lurking in the twilight shadows, and former allies are acting strangely hostile.
As divisions between the Clans grow deeper, Firestar's daughters face troubling decisions. One is torn between loyalty to her calling and a forbidden love, while the other struggles with her best friend's betrayal and the surprising perils of the forest. The choices they make now could affect ThunderClan for generations to come . . . and with an unexpected enemy preparing to attack, their courage and strength will be needed more than ever if the Clan is to survive.