Where to find ancient power in Pokemon white 2?

In Pokémon White 2, you can find AncientPower by battling certain wild Pokémon that naturally learn the move, such as Omanyte and Kabuto. Additionally, you can obtain the move through the TM (Technical Machine) found in the game. Specifically, TM 31, which contains AncientPower, can be found in the Celestial Tower after you have defeated the Gym Leader, Skyla.