Setting
The game takes place in the Kalos region, which was first introduced in the 2013 video games Pokémon X and Y. [9] The plot takes place during an urban redevelopment project in Lumiose City, which is based on Paris, [10] being undertaken by a company called Quasartico, Inc. [11] Nintendo of America has stated that the game takes place entirely within Lumiose City, where Pokémon coexist with humans in locations known as Wild Zones. [12] [13] During nighttime hours, Battle Zones appear for the Z-A Royale, where trainers wander and can challenge and be challenged by the player to Pokémon battles. The player character's goal is to advance from Rank Z to Rank A via promotion battles with certain trainers to have a wish granted. [7] During the course of the story, the Legendary Pokémon Zygarde takes an interest in the player character. [14] There is also a new, mysterious phenomenon within Lumiose City where wild Pokémon spontaneously Mega Evolve and go berserk. One of the player character's goals is to subdue these Rogue Mega Evolved Pokémon in the form of real-time boss battles similar to the Noble Pokémon battles within the prior title, Pokémon Legends: Arceus . [15]
Story
Five years after the events of Pokémon X and Y, Lumiose City had begun an urban redevelopment project led by Quasartico Inc. to restore the city's condition after an incident involving Team Flare, creating "wild zones" where Pokémon live in the city. The player character arrives as a tourist to Lumiose City, and befriends either Taunie or Urbain (if the player selected a male or female character, respectively), who gives the player their starter Pokémon: Chikorita, Tepig, or Totodile and brings the player to Hotel Z owned by the 3,000-year old AZ and his Floette. The player then joins the citywide Z-A Royale tournament where participants compete to rise from the lowest Rank Z to Rank A, with those reaching Rank A being granted a wish by Quasartico.
As the player easily defeats trainers in the lower ranks, they attract the attention of Quasartico and its CEO Jett, who recruits the player to handle "Rogue Mega Evolution", a recent phenomenon in Lumiose City resulting in wild Pokémon Mega Evolving on their own. The player's rank is raised to Rank F, and they defeat multiple Rogue Mega Evolved Pokémon throughout the city with the help of the Hotel Z-based Team MZ as they continue to progress in the Z-A Royale. In doing so, they also attract the attention of the Legendary Pokémon Zygarde. After defeating a former Team Flare member to reach Rank A, the player learns from former Team Flare leader Lysandre, now known as "L" having survived the destruction of the ultimate weapon due to Zygarde's intervention but cursed with the same immortality afflicting AZ, that a device called "Ange" within Prism Tower at the center of Lumiose had been emitting Mega Energy which had caused the Rogue Mega Evolutions. The player also learns that AZ was responsible for the construction of "Ange", which was activated by Team Flare's actions in X and Y.
The device is activated one night, leading the player and Team MZ to the tower. Taunie/Urbain successfully reaches the device with AZ's Floette, but the device malfunctions and transforms the tower into a gigantic, metallic plant monster threatening to destroy the city. With the help of other trainers from the Z-A Royale, the player and Zygarde successfully defeat the monster, Mega Evolving Zygarde and destroying the device. AZ watches as Ange is destroyed from Hotel Z and dies shortly after. After Ange's destruction and AZ's burial, Taunie/Urbain and the player agree to use their wishes from the Z-A Royale to restart the competition as the Infinite Z-A Royale. The player continues battling through the Infinite Z-A Royale, eventually facing Taunie/Urbain and AZ's Floette, with the player winning the match. The player and Taunie/Urbain are called to meet with Jett, revealing that Taunie/Urbain's mother is her daughter, making them her grandchild. Jett reveals her intention to step down as CEO with Taunie/Urbain replacing her, while they entrust AZ's Floette to the player.
The player also learns of the Legendary Pokémon Xerneas and Yveltal from Lysandre, who were both drawn to Lumiose City by Ange's activation. Working with former Team Flare members, the player draws out and captures them both, after which they return to Hotel Z to find Lysandre challenging them to a battle. The player emerges victorious, and Zygarde invites them to challenge it at a new wild zone at the ruins of Prism Tower. The player defeats Zygarde in all three of its Formes, allowing itself to be captured by them upon defeat. Lysandre returns to congratulate the player before departing the city, having decided to make the most of his immortal existence by atoning for his past misdeeds.
