The group sits together for bento lunches, during which Manatsu samples her friends' ingredients. Asuka then mentions how her family helps one another with the chores, inspiring Manatsu to make a bento meal inspired by Kururun.
Manatsu's friends postpone their club activities to study, with Manatsu revealing she is not good at it. Manatsu tries studying on her own, but finds herself struggling to do so. As such, her friends teach her how to study properly.
Manatsu and her friends are discussing their next club activity when the head of the school's disciplinary committee, Masami Kakuta, searches the room because of rumors of mermaid sightings in the school.
When the school's public announcement mentions rumors of a mermaid, Manatsu and her friends discuss folklore concerning mermaids, with Laura stating their singing talents.
As Manatsu and her friends go on a mountain hike, the Witch and Butler discuss the current situation and Laura, owing to the lack of Motivation Power being gathered because of her ability to reclaim it.
Picking up from the last episode, while Cure Summer and the other Cures search for Laura, the Witch warns Laura to not interfere with her efforts before sending her generals to steal more Motivation Power.
Manatsu and her friends discuss their school's newspaper requesting articles, with Minori bringing up ghost stories to put in and everyone decides to investigate ghost stories.
Manatsu returns to the clubroom after finding her lost wallet and discovers that the premium tropical melon bread she won in a lucky draw has gone missing.
As the Tropical Club enters their last day of camp, they try out many island activities while Manatsu prepares everyone for Minamino Island's festival.
The Tropical Club attempts to hang a banner, only for it to fly into Yuriko Shiratori's interview. Angered by the incident, Yuriko decides to suspend the Tropical Club when the six girls receive an invitation to a gameshow.
Manatsu and her friends plan a trip to the city's aquarium to see a new dolphin attraction. On the day of the trip, the dolphin attraction's wait time is too long, forcing them to look at other aquatic displays to pass the time.
Amidst anticipation for Aozora School's Cultural Festival, the Tropical Club decides to hold a makeup class, when Laura notices Minori distancing herself from the others.
An election for a new president of the school council is held at the school, due to the previous president, Yuriko, retiring. This excites Laura, and she declares she wants to become the new school council president.
A fashion modeller approaches Sango and her mother for help in a fashion show. Sango and her friends discuss it and discover Sango's passion for the show.
As the school prepares for their Halloween festival, Manatsu and Laura take interest in the costume competition. But then, a stray Yaraneeda attacks the festivities, and Manatsu and her three friends transform to fight it.
Laura and her friends receive an invitation from Grand Ocean to visit. Upon arriving there, are welcomed by the Mermaid Queen, who congratulates them for their progress as Pretty Cures and reveals the existence of the Marine Kuru Ring.
Picking off from the last episode, the Cures examine the damage done to Grand Ocean and stumble across a room housing seashells containing memories of mermaids who encountered humans, while Butler seals away the Marine Ring.
While practicing tennis, Asuka recalls her father approaching her for her incomplete future academic course survey, while Yuriko Shiratori resigns as president of the student council.
Sango stumbles across a fashion model audition on television and applies for it. Manatsu hears of her entry, but Sango admits that she is uncertain of what she wants to do despite wanting to follow her likes.
The Tropical Club makes plans for a play for the graduation ceremony, but Minori is hesitant about adapting her first story, despite suggestions from her friends.
The Tropical Club initiate making ideas for their play's plot, from how Manatsu met Laura and became a Pretty Cure, to chronicling how the others joined Manatsu and Laura on their adventures around the city and saving it.
Preparations for the "Tropical Graduation Festival" are underway throughout the school, and the Tropical Club is putting the finishing touches on their play.
Laura and the others head to the Witch's mansion in pursuit of Manatsu, who has been swallowed by a Yaraneeda. On the way, Laura learns the secret of the Legendary Pretty Cure from the Mermaid Queen.
With the former villains' help, the Cures fight the Butler Yaraneeda to recover the world's Motivation Power. He seems an unstoppable enemy, but the girls vow to do what's most important right now..
