Forest of Secrets is the third book in the Warriors series, written by Cherith Baldry and Kate Cary under the pen name of Erin Hunter. This individual book was written by Cherith Baldry. The plot is centered around Fireheart, a cat who gave up his life as a house cat to join ThunderClan, one of the four Clans of feral cats living in the wild. It takes up where the previous book left off.