In ages past, the Kingdom of the Vale, a mighty and flourishing realm, fell into turmoil. The ruler's two sons turned against each other, unleashing the powers of their Legendary familiars—Reshiram and Zekrom—and disturbing the Dragon Force that supplied the kingdom with energy. With the help of the Mythical Pokémon Victini, balance was restored and the Dragon Force was bound by the Sword of the Vale. Should the Sword be moved, devastation will loom again.

Damon, a descendant of the now scattered People of the Vale, is attempting to restore his people's kingdom to its former glory. He manages to summon Legendary Pokémon Zekrom, with the aim of lifting the Sword of the Vale and harnessing the power of the Dragon Force himself.

Meanwhile, Satoshi and his companions visit Eindoak Town, located at the foot of the Sword of the Vale. Confronted with Damon's scheme, they lend a hand to Victini, guardian of the Vale, in stopping the plan from coming to fruition and preventing a repeat of the tragedy that occurred a millennium ago.

[Written by MAL Rewrite]

Mythical Pokémon Keldeo wishes to join the Swords of Justice, a group of Pokémon traveling around the world, helping out those in need. To do so he must first harness the power of his horn and learn the move Sacred Sword, and he decides to challenge Kyurem, a Legendary Dragon residing in an abandoned mine located within an icy crater. Confident as he is at first, it soon occurs to Keldeo that he is not yet ready for the fight.

Meanwhile, as Satoshi and his friends travel across the Unova region, they stumble across an injured Keldeo. At the same time, Kyurem goes on a rampage, drawing energy from other Legendary Pokémon and disturbing the balance of power in the entire region.

Now backed by his new friends, Keldeo must overcome his weaknesses and face Kyurem once again, now with the fate of the world at stake.

[Written by MAL Rewrite]

The homeland of the Genesect exists no more. After three hundred million years, the snowy mountains where the Paleozoic Pokemon once lived are no longer habitable — but not all of the race are actually extinct. Several specimens are still alive and desperate to find a new place to call home. Led by a Shiny Genesect and accompanied by the Legendary Pokemon Mewtwo, the vagabond creatures arrive in New Tork City.

Perceiving the city skyline as similar to their initial habitat, the Genesect take over the city center, driving out other Pokemon and threatening the existence of the local populace. On top of that, the Genesect leader confronts Mewtwo in a cunning, fast-paced duel that is bound to destroy the entire city – and it’s up to Satoshi and his companions to save the city and reconcile the feuding Pokemon.

[Written by MAL Rewrite]

The story is set in Diamond Ore Country, of which Diancie is the princess.This is a country located deep underground, where the Pokémon Carbink live together in peace. The energy source of this country is a giant diamond called the Sacred Diamond, which can only be created by princess Diancie. However, the current princess doesn't yet possess the power to create such a diamond, and the current Sacred Diamond's power is soon going to run out, which would result in the end of the country. Diancie meets up with Ash and Pikachu, and set off together with them to search for the legendary Pokemon Xerneas, which possesses sacred power, but on the way, they find the cocoon where the Destruction Pokémon, Yveltal, who was said to have once destroyed life in Kalos, lies in wait.

(Source: serebii.net)