It starts with the blimp crashing on an island. Ash and Misty are traveling on a beach and they find some kids torturing a Lapras. Then the kids torturing it get into a Pokémon battle with Ash. Tracey comes along and tries to get all sorts of scientific readings on Pikachu. He more or less invites himself with the group.
Ash and his friends try to convince Lapras to go with them so they can take it back to the ocean, but it refuses to budge, it doesn't trust humans. Team Rocket shows up and predictably steals Lapras. Tracey's Venonat uses its radar eyes to find them, offering Ash a chance to risk his life (honestly, as if he could REALLY catch up to their truck using a bike and jump from one to another!) and win the trust of the transport Pokémon. Lapras decides to stay with Ash.