The heroine of the story, Amu Hinamori, is a student at Seiyo Elementary. At first glance, her classmates refer her "cool and spicy" and rumors speculate about her personal life. However, her real personality is that of a very shy girl who has trouble showing her true personality. One night, Amu wishes for the courage to show her "would-be" self, and the next morning finds three brightly colored eggs: - red, blue, and green - in her bed. These eggs hatch into three Guardian Characters: Ran, Miki, and Su. The Guardian Characters aid Amu in discovering who she truly is and help fulfill Amu's dreams.
Meanwhile, the Easter Company is extracting people's eggs in search of a special egg called the Embryo. The Embryo "Hopes and dreams of mankind" is believed to grant any wish to the one who possesses it.