On their way to Hearthome City, Ash & Co. meet Mira who offers to give them a shortcut using her Abra's Teleport. However, when they fail to arrive at Hearthome, Mira asks Ash & Co. for a favour, to help find a pendant that was lost at the bottom of sea. Reluctantly, Ash & Co. agree and go underwater. However, the pendant is found out to be a Pokémon's Pokéball, and is in some ruins protected by a Gyarados. Will Ash & Co. get the Pokéball and get to Hearthome in the end?

Taking Nando's advice, Ash and Brock decide to enter the Hearthome Tag Battle Tournament. In order to cheer her up following her contest loss, Ash also enters Dawn in the tournament. As everyone is paired up with their partners, Ash finds out that his partner will be none other then Paul! Things are just a strange for Dawn due to her partner, Conway, being a little to attached to her. Meanwhile, Brock gets lucky when he is paired with the beautiful Holly. As the tournament begins, Dawn and Conway, and Brock and Holly manage to pull off wins, but can Ash and Paul set aside their differences and work together?