Keldeo, a Mythical Pokémon, desires to become a part of the Swords of Justice, a group of Pokémon that aid those in need all around the world. However, before he becomes a member, he needs to master the use of his horn and learn the Sacred Sword move. As a result, he decides to challenge Kyurem, a Legendary Dragon living in an abandoned mine located in an icy crater. Although Keldeo is initially confident, he soon realizes that he is not prepared for the battle. At the same time, Satoshi and his friends are traveling through the Unova region when they encounter an injured Keldeo. Meanwhile, Kyurem causes chaos by absorbing power from other Legendary Pokémon, throwing the balance of power in the region into disarray. Now, with the help of his newfound friends, Keldeo must overcome his weaknesses and once again battle Kyurem with the fate of the world on the line.