The episode begins with Ash, Misty and Brock thinking that they are in the Safari Zone, and Ash spots a Chansey in a bush. He gets ready to throw a Poké Ball; however, the Chansey turns out to be Ranger Jenny in a Chansey hat. She points a rifle at Ash then arrests him for Pokémon poaching. She takes the group back to the station and explains that they are in a Pokémon Preservation Area where it's illegal to catch Pokémon.
Ash tells Officer Jenny he didn't know, so Jenny lets them off with a warning. Almost immediately, she sees a red dot on her radar, signaling that there are more poachers; Ash offers for him and the group to help. Jenny accepts, and the whole group travels to the location by the jeep that she drove them to the station in. They drive up to find Team Rocket trying to capture a group of Kangaskhan. Ash looks at his Pokédex, which says the Kangaskhan charge when in danger until they feel their young are safe. Team Rocket fires a rocket and scares all the Kangaskhan, making them charge towards the jeep. The group manages to escape, but Team Rocket traps all the Kangaskhan in a net.
Jessie throws a Poké Ball, but it is hit by a boomerang and sent flying back at her. Suddenly, a kid begins to yell, cutting the net and setting the Kangaskhan free. The Kangaskhan attack Team Rocket, blasting them off.
The kid jumps into the pouch of the biggest Kangaskhan. A helicopter soon lands and two adults come out, saying they heard a report of their missing child in the area. They all go back to the station and they hear that Tommy, or Tomo, is living in the area. Ash, Brock, Misty, and Pikachu leave the jeep and go look around for the infant Kangaskhan that should be in the pouch Tommy was riding in. They manage to find it, and give it a Super Potion since it is injured.
The kid sees the infant in pain when the potion stings its wound slightly, thinks they are hurting the infant Kangaskhan, and he jumps down. He then asks Misty, "You people or Pokémon?" Misty punches him and says that they are people. The two adults who earlier claimed to be Tommy's parents run over and talk to Tommy thinking he will remember them. He doesn't at first and claims the Kangaskhan are his family. His father smacks Tommy with a piece of wood, hoping that it will knock the memory of his parents back into his head. He remembers his mom,but not his father. His father opens his shirt and Misty smacks the father with a piece of wood, saying, "One memory at a time!" Jenny rushes back because her radar shows more poachers, and Tommy runs to the Kangaskhan to help.
They find a giant robot Kangaskhan made by Team Rocket. It pretends to be injured to persuade the other Kangaskhan to go help it, but their leader tries to stop them because it senses something amiss. However, they ignore their leader and go to help the "injured" robot anyway so, the trap works, and they are all hit by tranquilizers and fall asleep. The leader goes to take revenge on Team Rocket but is hit as well.
Ash then brings out his Pokémon: Bulbasaur and he uses Vine Whip and Squirtle tries Skull Bash, neither work. Team Rocket powers up for an attack, but the Kangaskhan break free. Pikachu and Charmander come out while Tommy throws his boomerang, when hits the fuel tank cover knocking the gasoline out, and Charmander's fire sets it ablaze. Though the robot is on fire, it doesn't slow it down.
Suddenly, the helicopter comes in and crashes into the mechanical Kangaskhan. It explodes, and Team Rocket "blasts off again". Tommy thinks his parents are dead and begins to cry, but they get up. They are revealed to be wearing similar things as Tommy and they say they will join Tommy, much to Tommy's delight.
The episode ends with Tommy, his parents, and the infant Kangaskhan in the leader's pouch waving goodbye as Ash and his friends are leaving.