When Amu meets with the Guardians, Tadase, Nadeshiko, Kukai Soma, and Yaya Yuiki, she discovers that they also have Guardian Characters and they invite Amu to join. After Amu encounters a third-grade admirer, Suzuki, and an X Egg forms from his heart's egg, Amu transforms into Amulet Heart and purifies the X Egg.
In addition, four DVD artbox compilations were released.
The first three compilations are composed of thirteen episodes, while the fourth compilation is composed of the last twelve.
The first artbox compilation was released on March 19, 2008 with the final artbox compilation released on February 18, 2009.
People view Amu Hinamori as a "cool and spicy" girl; Amu is actually timid and easily scared.
The next morning, after wishing for the courage to be her "would-be" self, she discovers three colorful eggs—red, blue, and green—in her bed.
At school, the eggs draw the attention of Tadase Hotori, whom Amu develops a crush on and confesses to in front of the entire school after a Character Change. Others are also interested in the eggs as Ikuto Tsukiyomi and his Guardian Character, Yoru, attempts to steal them.
One of the eggs hatch and Ran, Amu's Guardian Character, emerges to help Amu out and along with the Humpty Lock, stolen by Ikuto earlier, Character Transforms into Amulet Heart. class, the blue egg begins to hatch, unbeknownst to Amu and Ran, and Miki, Amu's second Guardian Character, peers out.
Nadeshiko Fujisaki invites Amu to tea at the Royal Garden with the Student Council Guardians, along with a message from Tadase that he will tell her about the Heart's Egg. However, after seeing Amu and Ran in an argument over a Character Change, Miki runs off. Miki warns Amu that if she does not believe in her Guardian Characters, they will disappear.
The story follows Amu Hinamori, whose "cool and spicy" exterior belies her introverted personality.
When Amu wishes for the courage to be reborn as her "would-be self", she is surprised to find three colorful eggs the next morning, which give birth to three Guardian Characters: Ran, Miki and Su.
The series was first broadcast on TV Tokyo in Japan between October 6, 2007 and September 27, 2008.