Gible was abandoned in the streets by an abusive trainer, who left her behind. She was later found and brought to Professor Sycamore by Alain. Gible did not trust Sycamore at first, even biting his hand. Sycamore did not mind, since he wanted to befriend Gible and, as time went by, she started bonding with him.
She was later introduced to Ash Ketchum and his Pikachu after they took a Froakie who previously saved Pikachu from Team Rocket to the Pokémon Center. However, Team Rocket interfered and tried to take control of Garchomp by placing a mind-controlling brace around her neck. This caused Garchomp to go beserk and go on a rampage across Lumiose City, rapidly using Hyper Beam. Luckily, Ash managed to calm down Garchomp and break to brace off her neck while they were on the Prism Tower. She, along with Froakie, watched in terror as Ash dove down to save Pikachu, but was miraculously saved by a Mega Blaziken at last minute. Once the crisis was over, Garchomp returned by to normal and happily reunited with Sycamore.
She met up with Ash and his friends again to help demonstrate the power of Mega Evolution with Mega Stones. The demonstration was interrupted when Team Rocket showed up, stole to Mega Stone machine, and abducted Garchomp. While Sycamore was trying to find Garchomp, he thought of how he first met her and how Garchomp befriended him. Team Rocket tried to get Garchomp to Mega Evolve, even using the radio waves to subdue her, but Professor Sycamore and the heroes arrived at the scene with an unexpected appearance of a masked man called Blaziken Mask, who lent Sycamore the Key Stone. Once James and Sycamore pressed their Key Stones, Garchomp Mega Evolved. Mega Garchomp was furious, but Sycamore managed to get Garchomp to remember him. Mega Garchomp calmed down, then slashed Team Rocket's machine and sent them blasting off, with the help from Mega Blaziken and Pikachu. With Team Rocket gone, Garchomp returned to her trainer once again.
Since Mairin was in danger, Sycamore sent Garchomp to battle Team Flare grunt's Skorupi. Garchomp used Dragon Claw to counter Skorupi's Poison Sting. After the collision, Mairin, Sycamore and Garchomp retreated away from the grunt. Mega Garchomp was also used to stop Druddigon's Dark Pulse. Since Serena and Mairin planned on rescuing Chespie from Lysandre Labs, Sycamore called his Mega Garchomp back and joined the girls in the rescue mission.
|Hyper Beam||Lumiose City Pursuit!|
|Slash||Garchomp's Mega Bond!|
|Dragon Claw||A Towering Takeover!|
|+ indicates this Pokémon used this move recently.*|
- indicates this Pokémon normally can't use this move.