In this intriguing Pokémon adventure, "What's After the Movie" explores a world where two dimensions—our reality and the mysterious Reverse World—collide in spectacular fashion. The story begins five years after Newton Graceland, a scientist fascinated by the Reverse World, develops a device intended to harness the power of Giratina, the enigmatic ruler of that shadowy dimension. His original plan was to use Giratina's abilities for travel between worlds, but when Newton discovers that the device's process would ultimately kill Giratina, he prudently abandons the project, deleting the blueprints. However, Newton's assistant, Zero, remains haunted by the knowledge, setting the stage for future conflict.
The narrative escalates as a catastrophic collision occurs—time and space, two fundamental dimensions that should never have intersected, unravel, causing chaos in both worlds. This turmoil leads to a fierce confrontation in Alamos Town between Dialga, the Pokémon of time, and Palkia, the Pokémon of space, who mistakenly believe each other to have trespassed on their respective territories. Their battle results in severe distortions in the fabric of reality, polluting the Reverse World. Giratina, angered and disturbed by these disruptions, captures Dialga and drags it into the Reverse World, setting off a chain of events that profoundly impact both dimensions.
During this chaos, a Shaymin, a tiny, hedgehog-like Pokémon with the ability to produce beautiful flowers, gets caught on Dialga's back. As the portal to the Reverse World opens again, Shaymin seizes the opportunity to escape, using its powers to flee through the portal back into the real world. Dialga follows, disabling Giratina from entering the real world by trapping it in an endless time loop, which leaves Giratina vulnerable and stranded.
Meanwhile, Shaymin encounters Ash Ketchum, Dawn, and Brock, who are determined to help the tiny Pokémon reach the Flower Garden in the mountains. The garden is crucial for flower bearing, a process that allows Shaymin and its kind to migrate and grow anew. As they journey together, a portal unexpectedly swallows them, plunging Ash, Dawn, and Brock into the Reverse World once more. There, they come face-to-face with Giratina, who is intent on using Shaymin's unique powers to break into the real world. With quick thinking, Newton intervenes to rescue the group, while Giratina's aggressive stance forces Newton to send Shaymin, along with Ash and Dawn, back to the real world for safety.
Back in the real world, Zero launches an attack with his army of Magneton, Magnezone, and Magnemite, aiming to seize Shaymin's power. During a frantic escape on a departing train, Shaymin touches a sacred Gracidea flower, transforming into its Sky Forme—a deer-like, soaring version of itself that can fly and wield greater powers. The group attempts to reach the Flower Garden via ferry, but are pulled back into the Reverse World. Giratina surfaces for an attack as Shaymin's instincts trigger its transformation back to normal, causing Zero to capture Shaymin and forcing it to open a portal to Giratina’s return to the real world. In a panic, Shaymin inadvertently opens a new portal, which sends Ash and his friends to the Flower Garden in the real world, just as Giratina is released from its time loop captivity.
Giratina, now back in the real world, is captured by Zero, who employs Newton's device with the goal of absorbing Giratina's formidable powers and claiming dominion over the Reverse World. Newton, seeing the danger, shuts down the device, which releases Giratina, but Zero had already absorbed much of its strength. Giratina collapses from exhaustion, but Shaymin heals it, demonstrating its caring nature. Zero retreats to the Reverse World, causing environmental chaos as a glacier begins moving toward the Flower Garden. In response, Regigigas and a herd of Mamoswine are awakened to slow down the destructive glacier, highlighting the interconnectedness of Pokémon and their environments.
The climax sees Shaymin opening a portal that drags Zero back into the Reverse World, where his ship crashes into the advancing glacier. Dawn's Swinub and Buneary help freeze Zero’s ship, preventing him from causing further damage and destroying critical data about Giratina’s abilities. Giratina, exhausted but restored, heals the damage inflicted by Zero’s attack and provides Ash with a ride back to the real world before heading off to find Dialga. The movie concludes with Shaymin and its kind performing their signature flower bearing, preparing for migration, symbolizing renewal and hope. During the end credits, Newton reconciles with Zero, who is then arrested, while Ash, Dawn, and Brock express their gratitude by sending flowers to their families, reflecting the themes of friendship, healing, and the enduring bond between worlds and creatures.
