Ash, Iris, and Cilan finally arrive at Nacrene City, the location of Unova's second gym. When they arrive at the gym, which is located in the city's museum, the door is locked. They soon find out that some strange things have been happening in the museum. Ash, determined to have his gym battle, decides to head inside and find out what is happening.

After his devastating loss against Lenora, Ash heads to the Nacrene City Battle Club to train for a rematch. While at the Battle Club, his training proves useful for both Oshawott and Tepig. With renewed confidence, Ash heads back to the gym to battle Lenora yet again. Will he defeat Lenora and win his second badge?