While on the way to Nimbasa City, Ash and friends come across a Cubchoo that has been separated from its pack. They decide to help find the pack, but that proves difficult when another group of Beartic constantly attacks them.

With the subway going awry, Ash & Co have met up with the Subway Masters Emmet & Ingo who are helping them to get to the trains with their Pokémon on. However, things are not as easy as it seems as Meowth has betrayed them and the train is getting further and further away, with Nimbasa City cut off from the rest of Unova. Will Ash & Co. manage to get their Pokémon back?