Erin Hunter

The Empty City--"Lucky has always been a Lone Dog, roaming the busy city streets and relying on his instincts. Then the Big Growl strikes--a devastating earthquake that changes Lucky's world forever. For the first time, he must team up with a Pack, a group of former Leashed Dogs who have been separated from their owners."--Amazon.com. A Hidden Enemy--"After discovering a forest filled with prey and fresh water, Lucky and the Leashed Dogs are sure...