Team Rocket are fighting who gets to call. Giovanni calls them to hear the news of the base. When they say it is destroyed, Giovanni is frustrated since they have no success. Team Rocket decide they need to do something big. When Jessie's Wobbuffet comes out of its Poké Ball, the telephone booth crashes. The next day, the gang is awake - Brock cooks breakfast while Ash, May and Max brush their teeth. They hear something from a bush, so Skitty goes in and returns to May, looking scared. The Pokémon comes from the bush - it is a Spoink. However, it is missing a pearl.
Torkoal cries for Spoink's loss, so the gang decides to help Spoink find the pearl. Spoink and the gang go to search the pearl. Spoink demonstrates it slept and fell over and then the pearl fell off the cliff and lost itself. Brock sends Mudkip to help in the search. Spoink found its pearl and uses Psychic to put on its head. However, it is actually Igglybuff. A girl appears and sees her Igglybuff, bot Spoink goes away, making the girl cry. Brock and Max stop it in time, but Spoink is sad when it did not get the pearl yet. Next, they encounter a Voltorb and it uses Psychic to put on its head. The gang goes to give it to a boy who arrived, but are electrocuted by Voltorb.
Next, they encounter Electrode, so Spoink (seeing it is round) puts on its head, but Electrode explodes. The gang gives up, but Mudkip spots a round object - it is the pearl! Spoink puts on its head and goes away happy. Torkoal cries for the recovery. The gang comes to Spoink, but everyone falls into a hole, and not long after Team Rocket appear. Team Rocket say they are new and Jessie cuts a rope, so everyone is pulled up inside a net. Ash sends Corphish who cuts the net. During their fall, Spoink loses its pearl, with Meowth catching it. Jessie sends Seviper and James his Cacnea. Corphish attacks with Bubble Beam, but Seviper dodges and goes to wrap Corphish, but misses.
Cacnea attacks with Pin Missile, but the attack has no effect due to Harden. Corphish attacks with Crabhammer, knocking Seviper and Cacnea out. Corphish uses Bubble Beam and Mudkip Water Gun, blasting them off. Max sees Spoink without its pearl. Team Rocket got the pearl and Meowth thinks it would look good on boss's crown. The gang appears, but Team Rocket run away. They disappear into a crowd of people, attending a carnival. They search for the pearl and Spoink sees a juggler, so it takes one of its balls, but soon returns after the gang intervenes. Same goes with a fortune teller and her crystal ball.
Team Rocket wander around. James catches a Feebas and sees a man - the same man who sold a Magikarp to him. He offers them the Feebas, but Jessie remembers her encounter with the Feebas - it grabbed her hair. The salesman shows them a video where Feebas evolves into Milotic. James and Meowth are still not convinced, but the salesman tells them that he has family back home. Since they have no money, they give the pearl for the Feebas. Team Rocket put the Feebas to swim in the water, however... its color fades, revealing to be a... Magikarp. Jessie goes mad for such a rotten deal, but surprise is not yet ended - the gang appears.
The gang demands the pearl, but Team Rocket explain the event, so they run off to find the salesman. The gang needs to do so before them. The gang finds the salesman, so Brock and Ash have an idea. Brock hides and his Mudkip uses Water Gun on Feebas, revealing it to be a Magikarp. The salesman tries to get away, but is intercepted by Brock and demands the pearl. Team Rocket appear as well, wanting the pearl back. Spoink uses Psychic, placing the Magikarp on its head, but soon falls. Ash and the salesman fight and the pearl is released in Team Rocket's hands. Jessie sends Dustox to protect the pearl.
Ash sends Torkoal. Dustox attacks with Poison Sting, but fails due to Iron Defense. Torkoal uses Flamethrower, hurting Dustox. James sends Cacnea and uses Needle Arm, but fails due to Iron Defense. Torkoal attacks with Body Slam, knocking Cacnea out. Dustox attacks with Psi Beam, hitting Torkoal. Mudkip uses Water Gun, knocking Dustox out. Cacnea attacks with Needle Arm, but misses. Torkoal attacks with Overheat, knocking Cacnea onto Meowth, dropping the pearl. Max puts the pearl on Spoink's head, recovering it. Spoink uses Confuse Ray, hitting Cacnea and Dustox. Spoinks blasts them off with Psychic.
Max notices the salesman's gone, but they won't go after it. The gang leaves, waving goodbye to Spoink.
- Featured Pokemon: Electrabuzz, Steelix, Cacnea, Shiftry
- In the beginning of the episode, a classic Pokemon identification can be seen. In this episode, it is a Slowbro.
- The dub title is a play off the song "Diamonds are a Girl's Best Friend."
- This episode is featured on the Volume 7: Psychic copy of Pokémon Elements.
- On Pokémon.com, the title of this episode is erroneously spelled as "Pearl's Are a Spoink's Best Friend".
- This is the fifth time the Magikarp salesman has appeared in the anime, and the second time Team Rocket has acquired a Magikarp from him.
- In a brief moment, Spoink's nose is shown on its back.
- The footage of James looking up a Spoink TCG card is cut in the dub. Cards seen included Spoink, Seviper, Skitty, Lotad, and Mudkip.