Ash and friends have almost arrived at Hearthome City. Before they can continue their journey, a girl named Mira appears and says she will teleport them to Hearthome City. However, she ends up teleporting them to a nearby lake and asks Ash, Dawn, and Brock to help her retrieve her Grandma's pendant from the sunken town. When they get attacked by a Gyarados, Mira finally tells them the whole story. The so called pendant is actually a pokeball with one of Mira's old pokemon in it - a Sandshrew. After seeing how much Mira cares for it, the three decide to help her despite the lies she has been telling. (thetvdb.com)