When `kittypet' Rusty strays into the forest beyond his owner's garden and is ambushed by a wild cat, life as he knows it is over. After a brave fight, he is invited to leave the `twoleg' world and join Thunderclan, one of four cat tribes, to train as a warrior. Rusty becomes Firepaw and learns laws of the wild - hunting and fighting to protect the clan's survival.

When the fearsome Shadowclan threaten Thunderclan's territory his warrior skills are put to the test. But how can he protect the clan when he suspects their own deputy of trechery?