All the Tera Training students have returned to Naranja Academy. Clavell informs the students that those who have passed their tests will receive their Tera Orbs later. Dot notices that Bocco has failed her Implementation Test, the same outcome as Liko. However, Clavell and Geeta propose a competition called the Course Students Battle Tournament, in which each of the students will battle each other in a one-on-one battle, and, whether passed or failed, can Terastallize if they wish. This relieves Bocco and Liko, the latter deciding to give it all she's got.
As Ann and Dewott battle Luka and Roserade, Nemona meets up with Liko, Roy, and Dot. She points out that all the Gym Leaders are here as well, wanting to see how much the students have improved. Seeing Ryme and Larry talking with Geeta, Liko immediately notices that Grusha isn't here. The trio says that they're battling in the second half, which Nemona is looking forward to. Suddenly, Dot gets a call from Penny, who tells her to meet up quickly for a talk in the nurse's office, brushing aside Dot's objections about her being about to participate in the tournament before hanging up. Dot goes off to find Penny, leaving the others confused. Dot arrives at the nurse's office, where Penny startles her by coming out from behind a curtain. She shows Dot that the school is being hacked, and the culprit is Agepan, the suspicious teacher. Penny also reveals that Agepan is connected to the Explorers. After hearing that Dot and her friends have a long history with these people, Penny asks her to tell her more about them. After hearing that they are after the Black Rayquaza and Terapagos, Penny thinks they must be dangerous. Dot points out that Clavell showed them info on Terapagos sightings in Area Zero. Penny gets an idea about what they're up to, going with Dot to the principal's office. Dot realizes that they want to steal data on Terapagos from the PC in the office, and this is the perfect time since all the teachers are outside watching the tournament.
In the principal's office, Dot and Penny see that the PC is being controlled remotely. Penny tells Dot that right now, only the teachers’ PCs can connect to the principal's office. Seeing how the staff room was deserted, they decide to look for Agepan in the only other rooms with PCs: the art room, the biology lab, and the home economics room. Penny tries to stop the breach from the office while Dot goes to look for Agepan. As Liko and Roy watch the tournament, Dot calls them and says that the Explorers have infiltrated the school. Liko and Roy thinks it's Onigiri and Sandwich, and Dot tells them that a teacher is among them too. Dot has them spilt up to search for them. While she checks the biology lab, Roy goes to check the art room, and Liko goes to the home economics room. As Liko passed a security guard, Roy arrives at the art room. Roy doesn't find anyone there, nor does Liko in the home economics room, so Dot thinks Agepan must be in the biology lab. Suddenly, Liko hears a crash from outside the room and finds the security guard on the ground covered in salt. Liko realizes it must have been Salt Cure and sends out Hattrem to use Heal Pulse on the guard and his Psyduck, who points Terapagos and Floragato upstairs. Hattrem stays to look after the guard while Liko heads upstairs, telling Roy and Dot that Onigiri is definitely here. Coming out of the art room, Roy is suddenly confronted by Sandwich, who reveals herself as Coral. Roy demands to know what they are up to, and Coral dodges his question and initiates a battle. Meanwhile, Sidian is on the school rooftop, having secured an escape route before Liko arrives and confronts him. Dot spots Agepan in the biology lab and takes a picture of her hacking the school. Medicham suddenly appears outside and alerts its Trainer to Dot's presence. Agepan also undoes her disguise and reveals herself as Chalce. Sidian tells Liko to hand over Terapagos, but she refuses. Sidian questions Liko what a mere child can do, and Liko says that she can fight.
Grusha appears in the library and heads upstairs, finding the guard on the ground as Hattrem leads him upstairs. Dot tells Quaxwell to break down the door with Liquidation, but is thrown against the ceiling by Medicham's Confusion. Penny makes a clip to catch Chalce in the act, but it disappears. Meanwhile, Coral has Glalie use Blizzard, which Fuecoco dodges. Roy commands the Fire Croc Pokémon to use Flamethrower, but then stops him so that it won't burn everyone's art, to Coral's personal confusion. Roy takes the battle outside, with him and Fuecoco riding Kilowattrel out the window they can fight outside without causing damage to the school. Coral and Glalie follow suit, allowing Fuecoco and Glalie continue their battle by exchanging a Flamethrower and Blizzard clash. On the roof, Liko commands Floragato to use Magical Leaf, which Garganacl counters with Salt Cure. Garganacl follows up with Stone Edge, which Floragato jumps off of before landing a hit with Magical Leaf. Garganacl uses Salt Cure, which Floragato evades and closes in with Quick Attack. As Garganacl is about to grab Floragato, she wraps her vine around the top of the Rock Salt Pokémon and breaks its hands with Acrobatics. Grusha is watching through the window as Sidian commands Garganacl to use Recover, growing its hands back. Sidian then reveals his Tera Orb and Terastallizes Garganacl into a Rock type, which worries Liko. As Quaxwell takes Medicham's attacks, Tinkatink sneaks into the lab through the top window. Before Chalce can react, Tinkatink smashes the laptop she was using. However, to Penny and Dot's dismay, Chalce has already gotten all the data. She recalls Medicham and sends out Xatu to Teleport her away.
As their battle on the roof continues, Sidian commands Garganacl to use a boosted Salt Cure. Floragato jumps to dodge, but her legs are still grazed by the enhanced stream of salt. A nervous Liko commands a Magical Leaf, but it barely does anything to faze the Terastallized Garganacl while Sidian mocks Liko's weakness. Garganacl heals itself with Recover again while Floragato falls to her knees and gets covered in salt crystals from Salt Cure's effect. Sidian again tells Liko to hand over Terapagos. Grusha is about to step in, but Liko refuses to give up, declaring that for Terapagos and the school, she can't afford to lose. With Floragato letting out a determined cry, Liko Terastallizes her. Garganacl uses a boosted Stone Edge, but Floragato leaps on the air to dodge it before using a boosted Magical Leaf. Garganacl counters with Salt Cure, but Floragato redirects her attack, which deals the finishing blow to Garganacl to defeat it. Sidian recalls Garganacl and tells Liko to remember his name, before flying off on his Aerodactyl.
Meanwhile, Fuecoco and Glalie continue to use Flamethrower and Blizzard, each trying to overpower the other. With Roy's encouragement, Fuecoco eventually pushes through, Coral shouts at Glalie to use more power, but by then, it's too late; Fuecoco's Flamethrower overpowers Glalie’s Blizzard and knocks it out. As Coral throws a tantrum over her loss, Chalce contacts her to withdraw. Coral refuses, wildly urging Glalie to get back up, but Sidian carries her off with Aerodactyl, much to Coral's anger as she recalls Glalie. As Liko watches them leave, Grusha comes out. Liko is a bit nervous, and Grusha sternly tells her to meet him at the principal's office, leaving her even more worried as she Terastallized even though she failed her test.
In the office, Liko stands before Clavell, Geeta, and Grusha. Clavell starts by saying that she Terastallized in battle even though she failed her test, and Liko reluctantly agrees. Grusha asks Liko if this is really the kind of person she is. Liko begs Grusha for forgiveness, but he rebukes this, saying that he's the one who should be sorry for misjudging her the way he did. Grusha understands now that when Liko fights on someone else's behalf, that's when her real strength shines through. Clavell praises Liko for protecting the academy, and Grusha passes Liko for her results, to her shock. Clavell and Geeta say that earning Grusha's respect and fighting for what's right makes her worthy of a Tera Orb as a Pokémon Trainer. Liko is pleased to hear this, feeling proud of herself while she thanks the staff.
Dot and Penny talk on the phone, saying that while Chalce got away with the data, they were still able to prove she was the intruder and mitigate the damage done to the school. Penny thanks Dot for her help before hanging up. Outside, Roy and Dot congratulate Liko for passing, the trio now being able to Terastallize anytime they want. With the second round of the tournament getting underway, Dendra shows Liko who she will be facing. To their shock, Liko and Roy find out they'll be battling each other.
