Hapu and the others admire Kiawe's new Flyinium Z that he received from Tapu Fini the previous day. Then, Ash spots a book on a nearby bookshelf, and its front cover features the mysterious man he and Kiawe met yesterday. The pair takes a closer look, and Hapu confirms that it is her grandfather, Sofu. Hapu is not surprised that the pair met her grandfather and admits that Tapu Fini is rumored to have the ability to summon the spirits of the departed. The confession takes Mallow by surprise, though only Lana notices this. Lillie then adds that Gladion was hoping to see their father. Hapu empathizes with Lillie's sentiments, but warns that people have not returned from Tapu Fini's mist. She clarifies that for meeting a loved one and having to say goodbye a second time may be too painful, and that is how people become trapped in the mist – a world between the living and the departed. Mallow suddenly leaves, and Lana confirms that Mallow's mother fell ill and passed away. Lana assures everyone that she'll be fine, and leaves the group to comfort Mallow.
Mallow and Lana talk things over on a park bench. Mallow declares that she doesn't wish to see her mother again as she begins to reminisce about the past. She recalls that while walking through a forest with her mother, who had recently left the hospital, they came across a wild Bounsweet. Mallow's mother caught it on Mallow's behalf. Shortly after, Mallow's mother was readmitted to the hospital. Mallow tearfully admits that she declared her hate for her mother's incessant apologies, and that it was the last thing she said to her before her mother passed away. Lana puts her arm around Mallow's shoulder and comforts her friend as Tapu Fini watches from afar.
Later on, Hapu leads everyone to her Ancient Poni Path home for a stay over visit. Mallow apologizes to Tsareena for worrying her, and also assures everyone that she is fine. Sophocles's mind is on playing games, but Mallow is quick to remind him that they have daikon seedlings to plant first. The group plant the seedlings and then water them. Elsewhere, Gladion is busy training his Silvally and Lycanroc as a peculiar mist begins to drift in. Hapu and the others find themselves caught up in the odd conditions, though Kiawe, Lana and Sophocles manage to locate Hapu. Mallow finds herself wandering around, Ash, his Pokémon, and Rotom are lost in the haze and Lillie is becoming increasingly anxious.
Lillie soon finds her older brother Gladion within the mist. Hapu informs everyone that this must be Tapu Fini's mist and explains that the missing people must be trapped within it. Ash runs after Torracat who lets out a cry as it searches desperately for something. From the mist, Torracat's old friend Stoutland steps into view. Ash recalls how he first noticed Stoutland was missing, but is happy to see Torracat proudly showing off its new moves. With Stoutland's assistance, Torracat begins training to learn a new move: Fire Blast. Lillie and Gladion continue to search for their father, though Mallow soon comes across her mother. Mallow rushes towards her mother and embraces her as tears well in her eyes. Mallow's mother is happy to see her daughter and Tsareena. Mallow soon breaks down and apologizes for her hateful comments, but her mother admits that she should have thanked her instead. The comments lead several Gracidea flowers to bloom around them, and Mallow goes on to thank her mother for her life and the friend she has in Tsareena. Soon a meadow filled with Gracidea flowers surrounds the pair.
Meanwhile, Hapu orders Lana, Kiawe and Sophocles to stay at her house as she looks for everyone. Hapu then sets off on her Mudsdale. Elsewhere, Ash watches on as Torracat's Ember attack soon develops into a fully-fledged Fire Blast. Hapu and Mudsdale soon reach the Ruins of Hope. Hapu then dives into the rock pool and reaches the shrine altar to confront Tapu Fini. She orders that Tapu Fini return Ash, Lillie and Mallow before it is too late, and she becomes frustrated when the island guardian performs a seemingly idle dance. Hapu decides to send out her Golurk to make her message loud and clear. She orders a Flash Cannon, and the attack almost strikes Tapu Fini when it seems to dissipate. Hapu's grandfather then appears and informs her that Tapu Fini has accepted her as the new Poni Island Kahuna because of her heartfelt gesture to save her friends, making Hapu very happy. Tapu Fini then lets out a shrill cry, causing the mist to clear. Mallow's mother realizes that her time with her daughter is limited and assures Mallow that she will always be with her and her family. Her mother soon disappears into the ether, and Mallow finds herself staring at a sunset over the ocean. She hears some rustling in the nearby grass, and a wild Shaymin soon appears out of it. Torracat exchanges a final nudge of affection with Stoutland before it also leaves.
Everyone soon assembles in Hapu's daikon garden patch. Mallow returns to her classmates with a Shaymin in hand, and Rotom quickly informs her that it is a Mythical Pokémon. Upon hearing Rotom's Pokédex entry data, Mallow asks Shaymin to stay with her until the upcoming Gracidea season, and Shaymin agrees. Mallow informs everyone that she saw her mother, while Ash says that he saw Stoutland. Lillie and Gladion, however, are disappointed not to have seen their father. Hapu arrives on the scene and states that this must mean that Lillie and Gladion's father is still alive somewhere. The revelation comes as a shock to the siblings, and Gladion eagerly prepares to rush off to inform Lusamine. Before Gladion leaves, Hapu tells him that he's free to challenge her to a grand trial when they next meet. The statement shocks everyone and Hapu then admits that Tapu Fini finally recognizes her as the new Island Kahuna. Ash eagerly asks for a grand trial against Hapu, but she tells him that she must first attend a ritual to formally receive the title, although she is more than happy to battle Ash once the ritual is over.
