Ash and friends return to New Bark Town, but before Ash is able to register for the Johto League Championship, Professor Elm sends him on an errand to retrieve a Pokémon egg from a nearby marine Pokémon laboratory. At the laboratory, Ash and friends meet up with a young researcher who uses the supersonic waves from a Lanturn to detect the singing voices of traveling Lapras.

On their way to Mount Silver, the gang come across a hot spring and meet Nelson who is looking for an Entei. Ash, Misty and Brock decide to release their Pokemon for them to enjoy the hot springs and hot sand. Team Rocket appear pretending to be researchers in order to steal Larvitar. After escaping from Rocket's truck, Nelson and his Misdreavous meet Ash again.Nelson wants to battle Ash, so Ash sends out Phanpy first.