Book Two: Spirits has 14 episodes. It is the second season of The Legend of Korra and expands the story from Republic City into the spiritual history of the Avatar world.
The season begins with Korra confronting a growing conflict between humans and spirits. Its central storyline introduces Unalaq, the chief of the Northern Water Tribe, and explores the origins of the Avatar through the story of Wan, the first Avatar. The two-part episode “Beginnings” is especially important because it explains how Wan joined with Raava and began the Avatar cycle.
Book Two aired in the United States from September 13 to November 22, 2013. Its finale consists of episodes 13 and 14, “Darkness Falls” and “Light in the Dark.” The season’s 14-episode count is easy to confuse with Book One’s 12 chapters or Book Three and Book Four’s 13 chapters each. Together, the four books total 52 episodes.