Ash and friends are continuing their journey when a group of kids suddenly appear in front of them. They begin throwing mud balls at Ash and his friends and as they run off, a Trubbish steals Ash's hat. They then give chase.

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.