In a bygone era, a legendary being named Hoopa, feared for its ability to vanquish even the most renowned Pokémon, was ensnared within a vessel by a solitary wanderer. This container was concealed in a remote desert cave, safeguarded to ensure the contained darkness remained dormant indefinitely. Generations later, a young man stumbles upon this vessel, breaking its ancient seals and setting loose the bound power. The liberated essence materializes as Hoopa's ominous shadow, determined to obliterate the bottle and thwart any further containment. In a fierce confrontation, the shadow engages the original Hoopa, sparking a chaotic clash as both summon legendary allies to their aid. Amidst this upheaval, Satoshi, a fledgling Pokémon trainer hailing from Kanto, and his comrades find themselves entangled in the turmoil. Now, they must unite to quell the rampaging Pokémon or witness a cataclysmic showdown of mythical proportions.