Tsubomi Hanasaki, a second year middle school student, relocated to Kibougahana with her family to live with her grandmother. Despite being shy and introverted, she is committed to starting her new school life at Myoudou Academy with confidence. Recently, she has been repeatedly dreaming of Cure Moonlight's loss at the Great Heart Tree, and she's puzzled by its significance. Suddenly, two fairies from her dream materialize, and in no time, she becomes a legendary Pretty Cure, Cure Blossom! Later on, her energetic classmate and new friend Erika Kurumi joins her as Cure Marine, and the two girls pledge to work diligently to safeguard everyone's Heart Flowers against the evil gang, The Desert Messengers.