Korrina cries out in horror from the balcony floor as she watches the black suited trainer's Phantump attack Gurkinn with a Will-O-Wisp. It is now clear that the enemy's target is her grandfather and his knowledge of Mega Evolution all along, and the Trevenant that ambushed them only served to distract her and Lucario. She wonders who the mysterious trainer is, and notices that Gurkinn is having trouble moving around due to his leg injury. She fears that it will only be a matter of time before the enemy gets to him.

Meanwhile, Mega Lucario and Trevenant continue their clash on the balcony, and the elder tree rams its roots hard on the floor. The move knocks Mega Lucario off its feet and cracks the entire balcony's floor, causing half of it to collapse. Korrina gasps that it has used Bulldoze, and is astounded by the damage it caused. She knows that Mega Lucario will be in trouble if it manages to use the move again, and knows she must stay focused.

Mega Lucario hurls itself forward to grab hold of the roots of Trevenant, and Korrina compliments its strategy in preventing the elder tree to use Bulldoze again. However, Mega Lucario suddenly winces in burning pain, and Korrina realizes with a start that it has been burnt by Will-O-Wisp. The young Shalour Gymleader experiences a moment of desperation, as Trevenant's ghost type makes it immune to Mega Lucario's powerful fighting type attacks, and it has gained full control of the situation by using the most proper moves. However, she quickly composes herself, and knows that she has no time to despair.

Korrina still believes that seizing Trevenant's roots will give them a chance to win, and at the moment notices that one of the elder tree's roots extends through the cracks of the balcony floor and runs all the way down to the ground below. She bolts in realization that it is probably drawing nutrients to feed its power, and recalls how the black suited trainer asked about the height of the Mega Lucario statue. She now understands that the question was not intended to provoke her grandfather as she thought, but to assess the height of the tower in order to let Trevenant root itself. Gritting her teeth in anger, Korrina states that she will fight back because she is the Shalour Gymleader and also a Mega Evolution wielder. With that, she hops onto the extended root of Trevenant, and uses it to roller-skate her way down.

On the ground floor, Gurkinn is cornered to a pillar by Phantump's flames. He snickers that it is sarcastic for someone who seeks Mega Evolution to go as low as attacking an injured old man with fire. He knows that his opponent yearns for power, but questions if she really understands what Mega Evolution is about. The young woman demands to know what he means, and Gurkinn says a person who manages to obtain great power doesn't necessarily know how to use it properly.

He explains that Mega Evolution is an evolution that goes beyond evolution, like how Aggron becomes Mega Aggron, Aerodactyl becomes Mega Aerodactyl, and Ampharos becomes Mega Ampharos. For a very long time, a number of Pokemon were thought to be unable to evolve any further, just like Lucario. But one fine day in the past, his ancestors discovered the shocking truth that these Pokemon were capable of temporarily transforming into a more powerful form. The emergence of such an immense power unfortunately created unwanted situations as well, and at that time, many fights arose and the power of Mega Pokemon was exploited. For this reason, keepers like Gurkinn himself exist, who shoulder the responsibility to choose and judge suitable inheritors of the knowledge. In other words, Gurkinn has the authority to determine a trainer's worth to wield Mega Evolution, for Team Flare, he certain deems them unworthy wielders.

At that moment, Korrina breaks in front the front door and overhears the term 'Team Flare'. She hops towards her grandfather, and wonders if the black suited woman is from Team Flare. However, the young woman has no idea what Team Flare is, and Gurkinn hollers that she should stop pretending. With that, the old man sends out his Heracross, and raises his left hand, which is wearing a Key Stone woven glove identical to Korrina's. He places two fingers on the Stone to activate it, and Mega Evolves his Heracross.

Mega Heracross strikes at Phantump with the horn on its head, and Gurkinn wants to know how Mega Lucario is doing. Korrina replies that it is battling on the balcony, but Gurkinn snaps that he is asking about its status in the fight. Korrina admits bitterly that the opponent is having the upperhand, and Gurkinn tells her to call it down in order to consolidate their forces. Korrina complies, and Mega Lucario promptly breaks free from Trevenant to start descending by hopping along the statue in the center of the tower. As it lands, it delivers a downward punch towards the black suited trainer, who narrowly evades the attack.

Korrina and Gurkinn then head for the exit, but soon discover in astonishment that tree roots have overgrown the opening. Mega Heracross and Mega Lucario strike at the roots repeatedly, but more just seems to grow. The black suited trainer states that they have no way to escape from the tower now, and says Korrina was mistaken when she thought Trevenant extended root was for drawing nutrients from the ground. She reveals that the root actually served as a nerve to control all nearby plantation in the area, which has created a matrix to bind the Tower. Now that the building is completely engulfed, it is impossible for anyone to escape.

Gurkinn ponders in silence for a moment, and decides that they have no choice but to abandon the Tower. Korrina exclaims in disbelief, and thinks her grandfather must be out of his mind. She argues that the Tower is the fortress that holds the symbol of Mega Evolution as well as their clan, and it is their responsibility to safeguard it. However, Gurkinn calls her an idiot, and asks her to think clearly what Mega Evolution really needs instead of glamorous buildings like this. His words strike like a radical at Korrina, and instantly make her go silent. Gurkinn places his hands on Korrina's shoulders, and assures her that Mega Evolution will live on even if the Tower of Mastery is gone. The Shalour Gymleader finally understands what her grandfather is saying, and shares a nod with Mega Lucario.

Mega Heracross then fires off a Pin Missile while Mega Lucario unleashes an Aura Sphere, and both attacks merge to strike the statue at the horn on its chest. In the next instant, the whole tower quakes, and rapidly begins to crumble. The black suited trainer is bewildered that the statue's chest horn holds an activation trigger for the Tower's self destruction system, and Gurkinn grins that this was built as a last resort to safeguard the secrets of Mega Evolution following the historical fights he talked about.

The old man muses that throughout his life, he has conferred Mega Evolution to 16 different people through successor ceremonies in this Tower, which included her granddaughter Korrina, as well as a famous actress in the region. All these years, he only broke his rule once when he gave the Key Stone to a young boy, who did not go through a successor ceremony. To be honest, Gurkinn still cannot fully explain it, but something about the boy convinced him that he would be a rightful bearer, and he has a hunch that what he did back then was of great importance.

Gurkinn says it is necessary to break historically important rules and abandon historically important places sometimes, and he feels that this is that kind of time. He adds that the Key Stone he passed on to the boy was 17th and last one he had, which means even he is captured, he would have no extra Key Stones to surrender.

The Mega Evolution guru recalls the young woman saying she doesn't know what Team Flare is, and requests to know her identity, assuming that she is really speaking the truth. The young woman states that her name is Essentia, and wants them to remember her as Essentia in the Expansion Suit. She then flees the scene as the Tower continues to collapse.

Later, on a nearby cliff, Korrina's heart breaks as she watches the Tower of Mastery crumble into dust. Gurkinn tells her not to cry, and says the current attack shows how aggressive the enemy is, which implies that they would strike the Tower over and over again until they get what they want. That said, it is perhaps best to choose this option early. He states that there are certain things in life that they cannot change, and tells her granddaughter to hurry along and hide themselves.

Before Gurkinn leaves the scene, he steals a final glance at the collapsed Tower of Mastery, and hopes that the secrets of a certain Pokemon's existence will now stay buried together underneath the rubbles, for all he can do to safeguard it is to let it go unnoticed. With that, Korrina drapes her grandfather's arm across her shoulder to support him, and the two begin to depart from their clans' historical fortress…