Ash and his friends continue on their journey, and as they walk they discuss how to keep Pokémon in shape with good eating habits. As they are nearing the next city, Serena suggests that they take a break at the local Pokémon Center. As Bonnie reaches to get Dedenne out of her bag, she realizes it is missing. While the group searches, Serena finds it staring at some fruit on a tree, being its usual gluttonous self. At the Pokémon Center, Bonnie sees a beautiful woman and asks her to consider being her brother's wife. The lady turns Bonnie down leaves with her younger sister, who accidentally takes Bonnie's bag instead of her own. Ash suggests that he and Clemont have a battle. On the battle field, Clemont's Chespin begins with Tackle. Pikachu responds with Iron Tail, which hits Chespin. Chespin uses Vine Whip on Pikachu, who dodges. On the sidelines, two black ears pop out of Bonnie's bag, which are not, she realizes, Dedenne's. A Pichu runs out, and electrocutes Serena and Bonnie. To stop Pichu's electricity, Ash tells Pikachu to use Thunderbolt, and Pichu calms down. After using her Pokédex to identify the Pokémon, Serena asks Bonnie why Pichu was in her bag. Bonnie realizes that she picked up the wrong bag, and the group rushes back into the Pokemon Center, where Bonnie's bag is gone. Nurse Joy tells them the little girl who was previously at the center with her older sister had a similar bag. Nurse Joy informs the group that the girl has a big red ribbon in her hair. Clemont comforts Bonnie, who blames herself for losing track of her bag and Dedenne, and the group takes to the streets to search.
Elsewhere in the city, the little girl discovers Dedenne in her bag. While her older sister talks to a friend, the young girl runs off to find Pichu, who is one of her older sister's most precious Pokémon. Ash and his friends run down the city streets, asking about the girl wearing the red ribbon. After one false alarm, the group tells Bonnie that the Pichu's owner will probably return for it, and that Nurse Joy will notify them if she does. At a city park, the little girl with Dedenne is talking to herself. When Dedenne runs off to a doughnut truck, and the girl buys it a doughnut. Meanwhile, Ash and co. receive their first lead, and head towards the park. At the park, the girl has grown fond of Dedenne, but decides to head back to the Pokémon Center so that she can ask Nurse Joy if she has seen Pichu. She just misses Ash and his friends, who arrive at the park soon after she leaves. As Pichu and Pikachu play, Clemont wires up a machine to help. Bonnie starts crying, but Ash and Serena reassure her they will find Dedenne soon.
Clemont unveils his new invention, entitled the "Electric Wave Amplifying Device," which will amplify Pikachu's energy waves over a wide range so that Dedenne can pick them up. As Pikachu's Thunderbolt sends electric waves throughout the city, Dedenne hears them and jumps out of its pouch. Clemont notes he needs more electricity, so Ash asks Pikachu to supply more, but Pikachu accidentally breaks the machine,creating an explosion. The little girl's older sister, having seen the explosion, comes running into the scene, and sees Pichu. She introduces herself as Rena, but doesn't know about Dedenne. After the group explains, she says that Dedenne must be with her little sister, Rimu, who has disappeared, and the whole group decides to search together.
Rimu is already outside the city limits, following Dedenne, whom she thinks is leading her to the Pokémon Center. Rimu follows Dedenne into a vineyard. Rimu temporarily loses sight of Dedenne, but soon finds it holding a bunch of grapes in its mouth and being chased by a Beedrill. Beedrill kicks Dedenne, ripping a bow Rimu had put on its head, and Dedenne responds with a Thunder Shock, which seems to discourage the Beedrill. However, just as they think they're safe, it appears again, and this time with other Beedrill in tow. The swarm of Beedrill chase Rimu and Dedenne through the vineyard rows. Rimu trips and falls, and just as the Beedrill near her, they are hit by a Thunderbolt fired by Pikachu. Ash, Serena, Clemont, Bonnie, and Rena come running up the path, with Pikachu in the lead. Rimu is reunited with her sister and Pichu, but the Beedrill still remain. Pikachu and Dedenne get rid of them by using the combined forces of their Thunderbolt and Thunder Shock. Afterwards, both Bonnie and Rimu begin to cry from the stress all of the day's events. Ash's stomach growls, and they all laugh. As the whole group sits down to dinner, only Pichu and Dedenne aren't hungry, having been given too many treats from Rimu and Bonnie, who smile guiltily. The pair dreams about becoming Pokémon trainers, and having more adventures.
