With the systems down at the Cerise Institute due to a major snowfall, Goh decides to go home to visit his family. While waiting for his parents to arrive, he and Scorbunny spot a Cubone being bullied by a gang of Mankeys. When the Mankeys steal Cubone’s bone, Goh, Scorbunny, and some of his Pokémon decide to help Cubone get its precious bone back. Meanwhile, because Goh had left behind his present to his parents, Ash and Pikachu come looking for him, and after learning what happened volunteer to help. (Source: Wikipedia)
