One day, Mana Aida receives a wedding dress from her mother and grandmother that they had worn in the past. While thinking about who she would wear this beside someday, a mysterious man named Marsh appears, and Mana is thrown back into the past. She was happy to see her grandmother she loved and her old dog Maro, but she then realizes that Alice and Rikka aren't there because memories have been altered. In order to save precious memories, the future, dreams and hope, Mana transforms into Cure Heart.