Book Three: Change (易) is the third and penultimate book of The Legend of Korra, which ran for a total of thirteen episodes. Set two weeks after the end of Book Two: Spirits, the nomenclature refers to the changes induced by the energy shift of the planet due to Harmonic Convergence and Korra's battle with the Dark Avatar. Book Three was released on DVD and Blu-ray on December 2, 2014.