Happie emerges as a youthful inhabitant of Dodeka Tree, enduring constant bullying and accusations of weakness. Determined to shed this label, he seeks guidance from his idol Anpanman, requesting lessons in strength with expectations centered on combat prowess and heroic techniques.

Through observation, Happie witnesses Anpanman consistently choosing acts of aid—helping those in distress or solving everyday problems—over direct clashes with villains. This emphasis on community assistance over dramatic battles leads Happie to lose faith in Anpanman’s ability to mentor him, rooted in a misinterpretation of heroism’s true nature.

Happie’s disillusionment creates an opening exploited by antagonist Baikinman, who partners with Dr. Hiyari to unleash the gluttonous maggot Gringa, intending widespread chaos. This conflict drives the narrative core. While specific outcomes remain undetailed, Happie’s journey navigates reconciling his quest for physical power with an evolving grasp of heroism defined by service and safeguarding others.

His story remains confined to this narrative, without appearances in other seasons, films, OVAs, or spin-offs within the documented scope.