Avatar: The Complete Book Two Collection contains all the episodes of the second season, Book Two: Earth, which consists of four discs with five episodes each, with bonus features. Aang goes to the Earth Nation to continue his Avatar training to master the Earth Element, and his best friends Katara and Sokka go with him. They make new friends, including legendary Earth Bender Toph, and learn a secret about the Fire Nation, but Appa is captured by Sand Benders. Meanwhile, the Fire Nation has a nasty plot of trying to siege Ba Sing Se, the Earth Nation capital. Will the Fire nation be able to complete this takeover, or will Aang and his friends be able to defeat them?