Out in the woods of Route 8, the Vaniville group is finally reunited. Y rushes towards her friends in excitement as they do the same, and Shauna quickly notices that Y's hair has been cut short. Y jumps in surprise as she was not aware of it until now, and realizes that her locks must have been chopped off by the enemy's sword slash earlier. With that thought in mind, she wastes no time in informing her companions that they have a great crisis at hand, and relays to them what she overheard from Malva and Celosia's conversation.

After hearing Y's story, X makes his way over to the giant 'Tree', and Trevor is bewildered that it is the antler Pokémon which wrecked havoc in Vaniville. X flips out his Pokédex, and confirms that it is indeed Xerneas, the Pokémon that 'gives'. Tierno still has trouble digesting the news, and wants to know if Team Flare really plans to control the people held captive to transfer the 'Tree' back to their headquarters. Y swears that it is what she heard, and adds that the 'Tree' is supposed to be moved to some Absorber which connects to the Ultimate Weapon. Trevor and Shauna bolt at the term, as it clearly indicates some device created for mass destruction, and Tierno is certain that it must be incredibly powerful to be named 'ultimate'. Shauna cries that they cannot allow the 'Tree' to be moved, and Tierno fervently agrees that it would cause unimaginable casualties. Y is starting to get overwhelmed by her friends' uproar and tries to calm them down, but it is X who manages to quiet everyone when he states that it may be an opportunity for them.

Trevor, Tierno and Shauna turn to X with confused looks, and X explains that if Team Flare is planning to bring a labor force to move the 'Tree', they would certainly make a round trip and it would give them a chance to find out where the enemy's headquarters are. Tierno beams with realization at what X suggest, and Shauna exclaims that they will finally get to infiltrate the enemy's base in that case.

Shauna's words cause Y to gasp in shock, and she wonders what she means. Trevor quickly explains that while Y was away, the four of them have come up with the idea to turn proactive. In other words, instead of running away endlessly, they would be the ones to initiate an attack. Y frowns with uncertainty upon hearing that, and wants to know if X really agreed to the plan. X responds with a nod, and Y, after a moment of thought, declares that she objects to the idea, which catches X by surprise. Y points out that she doesn't think it is right to refrain from saving the people being mind-controlled to achieve their goal, and X clarifies that he isn't saying they wouldn't help them. Rather, they would just wait until they get to the enemy's headquarters before they execute both the rescue and attack at the same time.

Y, still not too convinced, agrees that making a surprise attack would be to their advantage, but queries how likely they are going to succeed in beating the enemy. Tierno understands Y's concern, and admits that while he and Shauna were the ones to come up with the idea, their chance of success really falls on X. Shauna strongly believes that they could count on X, and Trevor also thinks X should be strong enough since he wields the power of Mega Evolution, especially with both Kanga and Elec on his team. X voices out his plan to use both Mega Pokémon to sweep down the enemy fast and quick, and Y, after pondering on everyone's words, decides to follow their plan but states that priority should go to helping the people under mind control if any danger befalls them, even if she has to do it alone. With that, she sends out Fletchy, Croaky and Veevee, and tells them to give their best.

At that moment, Shauna's Skitty senses the approach of people, and alerts its trainer. Shauna believes that the enemy must be coming back, and gets everyone to hide themselves immediately. Soon, Celosia makes her return with the group of mind-controlled Vaniville residents, and is also accompanied by Essentia. Celosia leads them to the 'Tree', and makes contact with Xerosic, informing him that they shall proceed with the transportation. Xerosic wants Essentia to help ward off intruders during the operation, and the mysterious trainer acknowledges the order with her usual mechanical voice. Xerosic wants to know if Celosia's Aegislash is really ready for job, and Celosia is surprised that he has doubts about something Malva experimented herself. The purple-haired Scientist tells Xerosic not to worry and simply get the Absorber ready, and orders the Vaniville residents to start working.

Carrying diggers that are made of wooden frames equipped with wheels and spade-shaped ends, the mind-controlled residents surround the 'Tree', and start to dig up its roots. Celosia wears a grin as she sees the 'Tree' being uprooted bit by bit, and suddenly notices something lodged in the blue cloth attached to the hilt of her Honedge. She checks to see that it is a lock of blonde hair, and realizes that Honedge must have slashed off the hair of someone. She rationalizes that what she sensed was correct after all, and there was indeed someone eavesdropping on her conversation with Malva behind the boulders earlier. She steals a glance at Essentia, and thinks the mysterious trainer may get to play her part soon in that case. Among the residents, Grace has her attention drawn to the lock of hair in Celosia's hand, and something seems to stir in her mind despite being under control.

Hiding being some thick tree roots, Shauna wants to know what Tierno thinks, and the big boy says although the bright light from the enemy's vehicles makes it difficult to see clearly, they are indeed trying to unearth the Tree just like Y said. Suddenly, he spots someone looking strikingly similar to the coach at the Dancing School, and on a closer inspection, realizes with a start that it is indeed the coach. On Trevor and X's side, they also make similar observations, and recognize the people in the group one by one, including Spencer from the old book shop, Morgan the fireman, the couple from the bakery, and Garcia from the valued store. Basically, all the Vaniville residents are present, who are said to have gone missing according to the news and others like Cassius.

Trevor recalls that when the two legendary Pokémon clashed in Vaniville, their explosive powers blew away Shauna's Furfrou as well as a Pokédex and Fennekin he received from Prof. Sycamore. He believes that these residents must have been blown off similarly, and somehow ended up in the hands of Team Flare. He states that the ambush from the Sky Trainer School's students yesterday proves the theory, and suddenly realizes that Y's mother must also be among the residents if he made the right assumption. Quickly looking up, Trevor sees that Y is eyeing the crowd closely, and knows that she must have figured out what is going on as well and is searching for Grace.

Just then, Grace approaches Celosia, and although her mind is still under control, she instinctively reaches for the lock of blonde hair in the Scientist's hand while keep muttering Y's name. Celosia is both annoyed and astonished that someone has managed to overcome Aegislash's spectral powers, and brutally pushes Grace away. The little drama catches Y's attention, and the girl lets out a gasp as she watches her mother tumble onto the ground. Without thinking, she leaps down from the tree where she is hiding, and dives straight towards Celosia, causing all her friends to cry out in horror. Unfortunately, Y forgets that her flying suit has been damaged, and ends up crashing down. Celosia giggles that she must be the one eavesdropping earlier, and wastes no time in delivering a stab with her Honedge. Just as the sharp blade is about to make contact, Marisso jumps in and shields Y from the hit with the thick shell on its head. X hops out from his hiding place, and orders both Marisso and Salame to guard Y. He then calls out Elec and Kanga, and sends them after Aegislash and Honedge respectively. Raising his arm, he lets out a roar and activates his Mega Ring. However, to everyone's shock, nothing happens, and neither Elec nor Kanga manage to Mega Evolve.

At that very instant, Trevor knows that their plan has been doomed. Not only has Y shown herself, but X has also failed to use Mega Evolution, and Shauna, Tierno and himself, out of panic, have exposed their hiding spots to the enemy. In the next split second, dozens of tree roots and vines break out from the ground. They rapidly close in on the group, and one by one restrain them as well as their Pokémon. Trevor is bewildered that the forest has attacked them, and X, who has been suspended upside-down, notices Essentia and her Trevenant, and realizes that the elder tree Pokémon has used its roots to control the trees in the forest.

Celosia thanks Essentia for her help, and greets the Vaniville kids with a smile, grateful that they are meeting again. She thinks their intention to thwart them has failed however, since their operation is complete. Apparently, the mind-controlled Vaniville residents have fully uprooted the 'Tree' and moved it onto a truck with chains, and are ready to leave the scene. Celosia tells Aegislash to start their way back, but suddenly changes her mind, and thinks she should finish off the kids first because getting rid of the worrisome buds is the key to prevent failure. With that, she commands a Slash, and Aegislash turns into its Blade Forme as it lunges towards X.

At that moment, something stirs in X's shadow, and lashes out to fend off the attack. X is astonished that his shadow has protected him, and soon sees that it was actually the work of a Gengar. Celosia demands to know who the intruder is, and her question is answered by Mega Lucario's surprise Bullet Punch, which forces Aegislash to revert back into its Shield Forme in defense. A voice comes on to say that they seem to have made it just in time, and everyone turns around to see the arrival of Korrina, Diantha and Gurkinn. Celosia is frustrated that the Mega Evolution Successors have come to interfere, while Trevor and Y are bewildered that not only the Shalour Gymleader but the top actress they met in the café in Lumiose have arrived.

Mega Lucario continues to keep Aegislash engaged, and Diantha orders her Mega Gardevoir to take on Trevenant. Up on another tree's branch, Malva grins that it has begun, and tells Braixen that every key player has finally arrived at the scene…