A new champion rises. An ancient king returns. A sorrow that has lasted 3,000 years is brought to an end.
In Lumiose City, masses of people of have gathered for a huge parade. A mother in the crowd tells her daughter how the Trainer at the stand in front of them is the brand-new Champion of Kalos. As the celebration goes on, a tall man in shagged clothes walks up the red carpet towards the stand. The little girl notices the man and recognizes him as the one from the story her mother has told her. Everybody quiets down as they notice the man reaching the stand. He addresses the new Champion, challenging him to a battle to find out what a "Trainer" is. Witnessing the giant man, the little girl starts recalling the story her mother had told her...
A long time ago, there was a man and a Pokémon, who both loved each other dearly. However, an age of war had begun, and the man's Pokémon was forcibly taken to fight at the battlefield. Several years later, the man's Pokémon was returned to him in a tiny coffin, having died in battle. The man, in his desperation to bring his beloved Pokémon back, regardless of the cost, constructed a machine, which restored his Pokémon back to life and granted it immortality. However, the man had suffered too much and was still enraged at the world that had hurt the Pokémon he loved, so he turned the machine he had built into the ultimate weapon. With it, he became a bringer of destruction who ended the war by wiping out both sides of the conflict. The resurrected Pokémon had learned that the lives of many Pokémon were taken to restore its life, and thus, chose to leave the man's side. The man, also granted immortality by his creation, now wanders eternally, desperately trying to find his Pokémon.
The battle between the man and the Champion comes to a close as the Champion's Chesnaught defeats the man's Golurk. The man recalls his Pokémon, and thanks the Champion for having freed him of his sorrow, the part of him that had built the ultimate weapon. Suddenly, something appears in the sky, and everyone turns to look up as the man's Pokémon, a Floette, descends down to rejoin him at last. The man is moved to tears as he gets to be with his beloved Pokémon for the first time in 3,000 years, and happily hugs it. In the crowd, the girl and her mother are also feeling happy for the two.