Meeting at Terminus Cave! (Japanese: ついの洞窟！動き出したZの謎！！Terminus Cave! The Mystery of Z is Set in Motion!!) is the 102nd episode of the XY series, and the 901st episode of the Pokémon anime. It first aired in Japan on December 24, 2015 and in the United States on April 16, 2016.
As our heroes enter Terminus Cave, Squishy takes off! Before the others can catch up, Squishy sends a message to a similar-looking Pokémon. This alerts Team Flare, and they scatter to catch Squishy (which they call Z1) and its friend, Z2!
As Team Flare closes in, Squishy summons many Cells and merges with them to become a fierce four-legged Pokémon. It hits Team Flare with a devastating attack—and when that’s not enough, Ash sends out his Greninja, and the two of them appear to battle as one being!
Team Flare finally retreats, but Squishy is missing. Our heroes set off to find it...as Team Flare watches their every move!
Ash and his friends arrive outside Terminus Cave. Squishy pops up out of Bonnie's bag to look. As they head inside, Team Rocket is spying on and decide to go and catch Pikachu. Inside the cave, Serena says that she heard the mine was abandoned years ago and is home to wild Pokémon. Squishy jumps out of Bonnie's bag and goes down a passageway causing the others to follow. Bonnie wonders if Squishy is looking for something. Serena calls Braixen to light up the area. Clemont uses his Clemontic gear to provide more light. As they crawl along a passageway, Squishy looks around nervously. They arrive in a cavern as Clemont wishes they'd taken an easier path. As they continue moving, Clemont becomes tired as Squishy heads to a gap and goes down it. Bonnie goes to follow but Clemont stops her saying it is dangerous.
Serena sees no way for them to get down as Ash brings out Noibat find an easier way. Clemont brings Luxray out to assist with its X-Ray vision. They soon find a passageway for them to take and they follow it. Team Rocket are behind them as Meowth wonders how far they will go. Squishy arrives in a cavern and looks around worried, unaware of a tracking device attached to a stalactite. Two Team Flare Grunts discover that Squishy has returned. They contact Xerosic and let him know about Squishy. Squishy reaches the water's edge and dives in as Luxray leads the others along a different path. Squishy starts to contact Z2 through telepathy AS Z2 replies back, unaware that the Team Flare Grunts have detected their conversations. With Z2's location found, Xerosic, Mable and Aliana go to find it. Squishy warns Z2 that is has to flee from its current location as Ash and the others arrive. Bonnie is relieved to have found Squishy and goes over to Squishy only for Squishy to disappear.
Outside, Bryony arrives and meets up with Celosia and after complaining about Bryony being late, they head inside after Squishy. The group are calling out to Squishy with no result. Ash walks into the water and calls out to Squishy. Squishy watches from a stalactite as Ash and Bonnie are attacked by Team Flare who orders them not to move. Drapion fires a Sludge Bomb which Celosia calls a warning with the next attack being a lot worse. A scout for Squishy reveals its location on the stalactite. Squishy falls into the water having missed being hit by Celosia's weapon. They continue to fire at Squishy as Ash and the others can only watch. Squishy is eventually hit, which forces it out of the water. Bonnie goes to help Squishy only for Drapion to fire a Sludge Bomb which Ash saves her from.
Clemont and Serena decide to battle as the Team Flare Grunts send out their Pokémon. Noibat manages to confuse Drapion before hitting Drapion only to be attacked by Bisharp. A Grunt goes to catch Squishy only to be stopped by Team Rocket who arrive on the scene. Ash brings out Greninja and orders it to free Squishy from Team Rocket. Greninja frees Squishy before dodging Drapion's attack. Ash, Clemont and Serena call for their Pokémon to attack as the Team Flare Grunts Pokémon blocks all the attacks, creating a lot of smoke. Celosia tells them that Squishy belongs to Team Flare. Bonnie says she will protect Squishy while the others ready an attack. This leaves Team Flare with little choice as Squishy starts to glow. It starts to gather Zygarde Cells and transforms into its 10% Forme. Squishy sends Team Rocket and Team Flare flying leaving Ash surprised at how much power that Squishy has.
Squishy leaves but Celosia and Bryony send out their Pokémon to chase after Squishy. Greninja and Pikachu stop them which allows Squishy to get away. Bryony orders her Liepard to attack which Greninja counters but is hit when Manectric uses Thunderbolt. Celosia and Bryony start to approach the others, not happy with their interference. Greninja gets up and starts to power up, allowing Greninja to change into Ash-Greninja. Ash orders Greninja to attack but gets hit, causing Ash some pain. Greninja sends Manectric and Liepard flying before Greninja returns to normal. Knowing they can't keep this, Manectric use Flash to blind everyone. Once Flash subsides, Ash and the others discover that Team Flare have left.
Outside, Squishy returns to its Core Forme and disappears. Celosia and Bryony receive a report that Squishy hasn't been located. Celosia is annoyed that it got away but Bryony is certain that it hasn't gone far. They notice Ash and his friends leaving Terminus Cave and note that they should keep an eye on them. They are confronted by Team Rocket before leaving which Celosia and Bryony find them a joke. Ash and his friends are calling for Squishy but can't find it. Bonnie vows to find Squishy, unaware that nearby, an invisible Squishy is watching them. At their base, Lysandre and Xerosic watch the footage showing Squishy having merged with its cells which makes it better able to move as Xerosic notes it will require much more study and they have yet to see the true power of Squishy. Lysandre inquires over Z2 which they are in the process of finding.