A wedding dress becomes a door to your own past, and suddenly Mana has to choose between the grandmother she lost and the friends she's about to lose. The movie doesn't care if you follow the logic of how any of this works, it only cares that you feel the cost of holding onto memory when time won't let you keep everything. The Precure girls fight not to save the world but to save each other from being erased from each other's lives, and the music breaks you open while they do it.

Mana receives a cherished wedding dress passed down through her family, only to be whisked into the past by a stranger named Matthew. There she is overjoyed to see her grandmother again, along with Maro, the dog she loved long ago, but her close friends Rikka and Alice are nowhere to be found. Her treasured memories appear to have been altered, and if nothing changes, the future will be ruined as well. A masked man with a strange clarinet also appears, calling himself Marsh, king of the Land of Memories. He builds a fortress in the sky, abducts people, and seals the Precure inside films of their own memories, blaming them for forgetting the things they threw away. A new fairy named Bebel reaches the Precure's fairies and tells them the girls must be freed to stop Marsh, who is himself being misled by the clarinet. The result is a magical girl fantasy film about the Precure fighting for their memories and their future.