Erin Hunter 
Warriors: Power of Three #2: Dark River 

Erin Hunters #1 nationally bestselling Warriors series continues with the second book in the Power of Three series!The second book in this third series, Warriors: Power of Three #2: Dark River, brings more adventure, intrigue, and thrilling battles to the epic world of the warrior Clans.Lionpaw, Hollypaw, and Jaypaw, grandchildren of the Clan leader Firestar, are thriving as Thunder Clan apprentices. Yet their new responsibilities bring new dangers, and each young cat is about to discover darkness: in the past, in the Clansand in themselves.