Into the Forest
A summary or opinion by yours truely! ;)
A young cat named Rusty starts his adventure when meeting a cat named Graypaw. After speaking with him, he soon learns that Graypaw is part of a clan called Thunderclan, He meets their leader, Bluestar, shortly after. After joining the clan, he realizes that it was going to be harder for him since he was an 'kittypelt' as the clan cats were 'clan born'.
To find out more you have to read the awesome book.