Princess Vanilla governs Ice Cream Land, a kingdom committed to producing delightful ice cream for all. Despite her royal status and widespread popularity among her subjects, she cannot create ice cream herself, despite relentless daily practice. This failure frustrates her profoundly, driving her to forsake her royal obligations and escape the palace.

During her travels beyond the kingdom, she meets Anpanman and Kokin-chan. Journeying alongside them through her homeland, she gathers fresh experiences and insights. This path leads her to uncover the core reason for her inability: she had lacked the vital understanding that genuine care and concern for others' happiness forms the essential ingredient in ice cream creation.

While she remains absent, the antagonist Baikinman exploits the opportunity to assault Ice Cream Land. He deploys his most powerful mechanical creation, the Baikin Ice Cream Robot, aiming to convert the kingdom into "Baikin Ice Cream Land." Princess Vanilla, now enlightened about ice cream’s true essence, unites with Anpanman to defend her realm. Her newfound wisdom proves pivotal in repelling Baikinman’s attack and safeguarding her people.

After successfully protecting her kingdom and possessing the knowledge of what makes ice cream truly special, she resumes her royal duties in Ice Cream Land.