Hiroshi Haneda (羽田ひろし), a third-grade elementary school pupil, stumbles upon an egg in his backyard. This egg hatches into Higepiyo, a small yellow bird sporting a beard. Hiroshi adopts Higepiyo as his pet, becoming the bird's primary caretaker and owner. He shoulders the responsibility of managing Higepiyo's mischievous tendencies, like consuming Hiroshi's homework, and keeping the bird out of trouble. Their bond forms the core of the series. Hiroshi frequently intervenes to curb Higepiyo's chaotic behavior, maintaining a relationship built on mutual care. He deeply values this connection and consistently demonstrates concern for Higepiyo's well-being.

Hiroshi also navigates typical childhood challenges, including interactions with a group of bullies. This group is led by his spoiled brat rival, Kumano Kazuo. These dynamics shape Hiroshi's experiences within his school and neighborhood environment. His efforts to guide Higepiyo through various escapades highlight his responsible nature despite his young age.