Tsunami vies to become the next queen of the magical kingdom Juraihelm. To secure her position, she must pass a test: selecting an Earth representative to restore the balance between good and evil. She chooses Sasami Kawai, granting her the power to transform into the magical girl Pretty Sammy. This portrayal diverges from other continuities where Tsunami appears as a cosmic entity or shares an existence with Sasami.

She displays a carefree, relaxed, and slightly ditzy personality. This is evident when she confuses Mozart's music for Beethoven's during her initial encounter with Sasami and fails to identify a cheesy-looking doll decoy deployed by her rival, Ramia. Largely oblivious to Ramia's active sabotage attempts against her candidacy, Tsunami expresses genuine grief upon Ramia's temporary disappearance, even posting public notices seeking her return.

Her core motivation centers on galactic-scale benevolence, including an ambition to "plant flowers across the entire galaxy" if crowned queen. Despite Ramia's schemes—such as transforming Sasami's best friend Misao into the antagonist Pixy Misa—she diligently continues her duties, utilizing Ryo-Ohki as an advisor for Sasami. Her story concludes with her successful ascension to queen after Sasami and Misao reconcile and unite to stop Romio's plan to crash Earth into the sun.

In other franchise depictions, like the OVA continuity and related manga, Tsunami is characterized as one of the omnipotent Chousin goddesses who created the universe. These versions depict her as eloquent, courteous, and fundamentally linked to the Jurai royal family through her creation of sentient Royal Trees, sharing an assimilated existence with Sasami Masaki Jurai. However, within this specific series, these aspects are absent; she functions solely as a magical realm candidate whose connection to Sasami is strictly that of a chosen representative.