Bonnie is sleeping in her room, when Clemont, wearing a white tuxedo, comes in to wake her up. Upon inquiry, he reveals that he is getting married and has decided to hand over the Lumiose Gym to his sister, absolutely shocking Bonnie. Clemont leaves the room, asking Bonnie to be dressed in beautiful clothes for the day. At the church, just as Clemont is about to get married, Bonnie rushes in the church, begging Clemont to stop. A horrified Bonnie wakes up in her tent, glad that it was just a nightmare and goes back to sleep. In the morning, as everyone gets ready for breakfast, she tells Serena about her dream but Serena raises her concerns by stating that dreams can sometimes become true. However, seeing another one of his brother's inventions blow up, she realizes that nothing of this sort will ever happen to her brother.
The group eats its breakfast, while Chespin, Pancham, Dedenne, Bunnelby and Pikachu play with ball. A pass from Chespin throws the ball into the bushes and Bunnelby goes to fetch it, where he meets a Buneary holding the ball and blushes after seeing him. Ash and his friends notice the two and Serena checks her Pokédex. Buneary's trainer comes to the scene and, seeing her Buneary with the group, asks her if they are her friends. Bonnie as usual gets excited at seeing another girl and asks her to marry Clemont. Clemont, blushing, takes her away with the Aipom arm, but Lilia says that the proposal sounds interesting and that she had been looking for a partner, flustering both Clemont and Bonnie. Lilia notices the Aipom Arm and Clemont claims that he made it himself, much to Lilia's excitement, while Bonnie seems pretty surprised about all this.
The groups sits by the lake side, Bonnie still suspicious and unhappy, when Lilia informs the group that her father works in the famous electronics company, Orangics, something which excites Clemont. Lilia claims that the Aipom Arm is more interesting to her than her company's robots, but Clemont reveals that inventing is just his hobby. Ash praises Clemont's inventing skills by mentioning Clembot, while an annoyed Bonnie calls him a blabbermouth in her mind. Clemont shows his inventions to Lilia, and Ash praises the Aipom Arm, revealing that the Aipom Arm has been helpful in a number of situations. Serena asks her why she is looking for a partner, and Lilia reveals that she is set to take over Orangics someday, and the partner she chooses will have to be ready to handle the pressure with her. At this, an anxious Bonnie starts daydreaming, continuing from where her nightmare ended. She envisions Clemont introducing Lilia to Bonnie in the church, handing over the Gym to her in favor of working in the Orangics, and living a happy life with Lilia; a flustered Bonnie asks Serena to pinch her in order to wake her up from her dream, but it fails. Lilia's stomach growls and Clemont begins cooking lunch for the group, which causes Lilia to be impressed and Bonnie to call Ash a double blabbermouth. Bonnie exclaims that she is hungry too but Clemont reveals that she just had lunch. Meanwhile, Bunnelby and Buneary are sitting by the lake, and Chespin and Pancham try to flirt with the Rabbit Pokémon, and are knocked away by her. Their antics are being viewed by Team Rocket, and Jessie wishes to capture Buneary to raise her beauty and charm. Alongside, James gets into an argument with Meowth for calling his Inkay unappealing.
A displeased Bonnie watches as Clemont offers food to Lilia, who is happy to meet a man who can cook. Bonnie begins daydreaming again, this time visualizing Lilia adding honey in Clemont's tea, feeding fruit to Clemont and Clemont declaring that he is the happiest man of them all, now that he is married to Lilia. Seeing Bonnie's unhappiness, Dedenne uses Nuzzle on Lilia. Clemont scolds Dedenne for his actions but Bonnie seems pleased with the Antenna Pokémon and secretly thanks him. Lilia walks up to Bunnelby and Buneary and advises them to go for a walk, prompting Chespin and Pancham to get angry. Lilia also asks Clemont for a walk to which he happily agrees. Bonnie is all puffed up, claiming that Buneary and Bunnelby going on a walk does not imply that their trainers have to do so as well and wishes that she not have proposed Lilia for Clemont.
On their walk, Buneary and Bunnelby sense danger and try to avoid a pit trap set by Team Rocket but Lilia and Bunnelby end up falling in it nevertheless. They go to their camp site; Clemont puts some bandages on Lilia's wounds, while Bonnie puts bandages on Bunnelby. Upset with how situations are turning out, Bonnie tries to confront Lilia and persuade her to not choose Clemont as her partner, but fails miserably, as she finds all of Clemont's mentioned habits to be adorable. When Ash and his friends head on to Snowbelle City, Lilia wishes to accompany them to the next Pokémon Center, annoying Bonnie, Pancham and Chespin. Clemont asks Lilia about her leg, who replies in the affirmative. Bonnie rushes forward and gets in between Clemont and Lilia (who are walking side by side), wishing to hold Clemont's hand, a thing she has never done before. The group is stopped in their tracks by Team Rocket, and everyone but the Pokémon fall in a pit trap beneath them. Team Rocket catches Bunnelby and Buneary in a net, and recites their motto. Pancham and Chespin try to help the captured Pokémon, but fail, and Team Rocket flees the site. Ash, Serena and Clemont get out of the pit, but Bonnie and Lilia are still stuck inside. Clemont offers help to Lilia (despite Bonnie being the one asking for the help, who nonetheless manages to get out on her own). Clemont comforts a worried Lilia by revealing his invention "The Protection Progress Machine", which uses the transmitters in the bandages applied to Lilia and Bunnelby for tracking purposes and thus will help the group in tracking Team Rocket's location.
Halting on a mountain cliff, Team Rocket is happy with their success, but is confronted by Clemont and his friends. Jessie and James send out Gourgeist and Inkay to fight. A Shadow Ball from Gourgeist is cancelled out by Chespin's Pin Missile, while Inkay uses Psybeam to counter Pikachu's Thunderbolt. Clemont sends out his Luxray, who uses Thunder Fang on the Pumpkin Pokémon. Gourgeist and Inkay use Shadow Ball and Psybeam, which are avoided by Pikachu and Luxray. The moves advance forward, narrowly avoiding Lilia and Bonnie but causing the latter to fall off the cliff. Clemont jumps to his sister's aid, using the Aipom Arm to lift her back up. Meanwhile, Pikachu dodges another Shadow Ball from Gourgeist, while Inkay gets hit by a Stone Edge from Pancham and Gourgeist strikes back on him with Seed Bomb. Concurrently, Clemont's Aipom Arm begins short-circuiting, but Clemont, with help from Luxray and Lilia, successfully lifts Bonnie to his arms, before the device fails. Clemont safely brings Bonnie to the ground, and everyone heaves a sigh of relief. Serena sends out her Braixen to use Fire Blast on Jessie's Gourgeist, while Electro Ball from Pikachu hits Inkay. Clemont is glad that Bonnie is safe, but Bonnie is worried that the Aipom Arm is not; Clemont assures her that he can fix it with ease and that her safety is of primary importance. As the two siblings hug, Pikachu uses Iron Tail to cut through the net and free Bunnelby and Buneary, then uses Thunderbolt to blast Team Rocket off again. Lilia is glad that her Buneary is safe and thanks everyone for their help.
Evening sets in, and Bonnie seems pleased. Lilia wishes farewell to everyone, and on Serena's inquiry, explains that she still has a lot to learn and that choosing a partner is not the kind of quick decision one makes over night. Lilia approaches Bonnie and advises her to be nice to her brother. Bunnelby waves goodbye to a teary eyed Buneary as well, and Lilia leaves the group. Bonnie claims that Clemont is fine the way he is, and the group heads on to Snowbelle City.
The next day, Clemont has successfully fixed his Aipom arm and Bonnie comes to see it. She notices a screw lying on the ground, and Clemont realizes that the device is not properly repaired, which starts behaving erratically and blows up. Seeing this, Bonnie realizes that finding a woman for her brother is, indeed, a good decision. Thus, she proposes to a passerby woman, as her brother asks her to stop it for the "millionth" time.