While visiting a big city home to many lively Pokémon, Pikachu rejoices when Satoshi, Kasumi, and Takeshi give their Pokémon free rein to play, with the only condition that they must all be at this rooftop in two hours. Unfortunately, Pikachu's leisure time is short-lived when he encounters a Pichu on a rooftop across the street. While bantering with each other, Pikachu nearly falls off the building. Following a lucky sequence of events, Pikachu finds himself safe next to Pichu and his brother—but on the opposite side of the road!

Because they are familiar with the area, the Pichu brothers volunteer to escort Pikachu back to his friends. As the trio stumble upon a series of obstacles on their journey across the bustling city, Pikachu starts to wonder if he will rejoin his companions on time.