Ash, Iris, and Cilan finally arrive in Castelia City and meet Burgh, but  they all discover that the city has shut itself down. When they  investigate the sewers, they discover and assisst a Venipede stuck in a  pipe, which, out of fear, Poisons Ash. Later, they see a whole swarm of  Venipede in the sewers, which flood the streets. Trainers with Fire  Pokémon do their best to fight the swarm, including Trip and his newly  captured Lampent. However, Ash tries to stop them from hurting the  Venipede, as hurting them will not get rid of them. Professor Juniper  studies the Venipede swarm back in Nuvema Town, realizing they must have  been pushed out of their natural habitat by something. Burgh tries to  figure out the problem in Castelia City when Trip continues to use  Lampent to get rid of the Venipede, Ash getting hit by a Shadow Ball in  the process. Nurse Joy arrives with her Audino calm down several of the  Venipede, and the Venipede which they helped earlier came and helped to  calm them. The rest of the group uses their Pokémon to gather the  Venipede into Central Plaza to keep the townspeople and the Venipede  safe. During this, Ash's Pidove evolves into a Tranquil, while Professor  Juniper discovers that something is emitting energy in the Desert  Resort just as Giovanni heads there to join up with Team Rocket. As the  mayor thanks Burgh, Ash, Iris, Cilan, and Trip for helping, Professor  Juniper flies in and tells everyone what is happening in the Desert  Resort. Ash, Iris, and Cilan head out with her to the desert as Burgh  promises he will let Ash challenge him for the Insect Badge when  everything is cleared up. 

 
