Veevee debuted as an Eevee in the Sylveon Enchants, with Y trying to bond with her, as Y had caught Veevee in a forest the day before. Y attempted to have Veevee mimic the faces she was making, hoping that it would form a subconscious connection between the two. Losing faith in the technique, X tells Y that she should be trying to mimic Veevee's faces and not the other way around. Y then attempts to just slow the Evolution Pokémon down, and has Froakie attempt to trap Veevee with his Frubbles, which Veevee easily dodges. Veevee then attacks Froakie with Baby-Doll Eyes, and satisfied with her victory, goes to sleep inside her Poké Ball. Later, Y begins to connect with Veevee by feeding her Poké Puffs and petting her.
Veevee is then drawn to a Game Corner, and Y decides to compete in its games with her to further their bonding. They first attempt a game where Veevee, Fletchy, and Froakie have to listen to Y's commands to hit balls of yarn with their heads at the right time. After only earning three points, Y angrily shouts that she will surely win the next one. Y then moves onto the final game, where she has to collect Berries that Veevee picks out. Soon into the game, the two are synchronized enough that Y does not need to wait for Veevee to tell her what Berry to pick. While picking out another Berry, a Sliggoo owned by Team Flare latches onto Y's head, with Team Flare threatening to release its corrosive liquid onto her if X does not hand over his Mega Ring. Veevee quickly jumps in to save her Trainer and is easily smacked away by Sliggoo, becoming drenched in its corrosive liquid. Veevee picks herself up and shakes off the liquid, revealing that it had evolved into Sylveon. Veevee knocks away the Team Flare Grunts with her feelers and finishes off Sliggoo with Draining Kiss, mimicking a face Y had made to her earlier. Y then hugs Veevee, crying with tears of relief.
In Scizor Defends, Veevee is used to help Y catch a wild Absol, utilizing her advantage as a Fairy-type. Not wanting to hit Absol with a powerful attack, Y has Veevee restrict herself to only using Swift and Quick Attack. After attacking the Disaster Pokémon with her feelers, Y was able to successfully capture it.
In Mewtwo Angered, Veevee is used against Aliana along with Solsol near the Pokemon Village, going up against her Diggersby and Pumpkaboo. The two are initially ambushed by Diggersby's Rototiller, slowing them down and making it hard to move around. Veevee counters with Disarming Voice against Pumpkaboo, who seems unfazed by the attack. Overwhelmed, the two are saved by Trevor's Flabébé. Later in the battle against Team Flare, Y catches up to X and has Veevee support him in battle. Veevee creates a Misty Terrain, saving a Mega Evolved Salamè from a super effective Dragon Pulse from Lysandre's Zygarde, halving the damage of the attack.