Shugo Chara!

The Guardians gathered around eating doughnuts. Then it shows the Easter workers reminiscing about the past when Nikaidou and Yukari were still working for Easter and when Utau was producing the Black Diamond CD's. Amu goes to talk to Tsukasa, and he tells her that changes are going to happen, and she might not notice it, but the people who pay close attention will. When Amu is heading home, it rains, so she stops under a tree. After saying Ikuto's name aloud, he pops down suddenly from the tree. To Amu's shock, she accidentally slips, leaving Ikuto preventing her from falling and the two talk. Ikuto mentions that Amu has changed somehow. Tadase shows up with an umbrella, gets angry, and fights Ikuto while they both Character Change. Amu decides to do something, and she Character Transforms to Amulet Heart. The Humpty Lock becomes more powerful and her transformation changes, the Dumpty Key responds to the power. The rain clears, showing a rainbow.

Amu is walking along when the Guardians meet up with her. Yaya praises Amu for her powered-up Humpty Lock. With her classmates, Amu goes to visit Manami's flower shop. Manami tells Amu that she dreams of being a florist some day. While Amu is leaving, Lulu de Morcerf shows up to see Manami. The next day, Amu brings Manami cookies for thanks when Miki and Su sense a Guardian Egg (Ran doesn't sense it, but plays along). Amu meets Lulu, and she learns that Lulu can see Guardian Characters. Ikuto sees Lulu walking up the Easter building steps and, after she passes him, stares at her with disdain. Later, Lulu meets Manami again and turns her Heart's Egg into a Mystery Egg using a special ruby necklace. The Guardian Characters sense this, and the Guardians go to Manami, who Character Transforms into Flower Dream. Amu transforms into Amulet Heart. She almost gets squashed by Manami, but gets powered up pom-poms to deflect her attack. After reasoning with Manami, her Mystery Egg turns into an X Egg, allowing a stronger Open Heart to purify her. At the end, Amu is with the Guardians, wondering if Lulu was connected to Easter and the events.

Lulu shows Kazuomi a book containing information about the Mystery Eggs. She then offers to shake Ikuto's hand but he refuses. Amu is standing outside a store when a girl walks out. The girl's cell phone rings, which Amu notices her ringtone is Heartful Song. The two talk, and Amu ends up agreeing to show the girl, Hitomi, Utau in-person. Amu is frustrated, but goes to see Yukari. After being rejected, Amu sees Utau out of the building. The two talk, but then Miki senses the presence of a Mystery Egg. They head off to see Hitomi hypnotized, singing and putting everybody in a trance. After Utau criticizes her, Hitomi Character Transforms to Singing Dream; Amu and Miki then transform to Amulet Spade. Amu's Colorful Canvas is overpowered by Hitomi's power, so Amu tries attacking with a new move: Prism Music, and succeeds. Utau then Character Transforms to Seraphic Charm and Angel Cradles Hitomi's Mystery Egg into an X Egg. This frees everyone else from the trance. Amu finally uses Open Heart to purify the X Egg and free her. The Embryo shows up, so Lulu tells Ikuto to grab it, but Ikuto had left earlier on. When Ikuto arrives home, his violin is missing; stolen by Easter.

Nagihiko returns, much to Kukai's surprise. When Amu sees him, she is told that Nagihiko would be the new Jack's Chair. Amu still believes Nagihiko is Nadeshiko's twin, even though they are one in the same. Rima is jealous and suspicious of Nagihiko, especially with his and Amu's friendship. Later, Amu is seeing hanging around Mamoru Mizuno who wishes to visit the town's Planetarium. Lulu notices this, so she plans to get to Mamoru after he leaves the Planetarium, but Amu sees her. Lulu brushes her off, angering Amu immensely. Mamoru later goes to the Guardians with his Heart's Egg turned into a Mystery Egg, and he Character Transforms to Space Dream. Amu Character Transforms to Amulet Heart. Thanks to the Humpty Lock; Tadase's, Rima's, Yaya's, and Kukai's transformations power-up. Using his powers, he lifts a lot of things off the ground. He tries to lift a rocket-style play set, but the Guardians hold it down. Amu gets roller skates, Heart Speeder, to chase after him. Eventually, Mamoru realizes he is in the wrong, changing his Mystery Egg into an X Egg. Amu then purifies the X Egg.

When Amu makes a high school boy, Yugaku Iwagaki, angry, she gets more than she bargained for as he chases the female Guardians all around the school. Amu later finds a deer figurine and puts it into the Lost and Found. After the chase, the female Guardians return to the Royal Garden, finding Kukai and Tadase in female school uniforms due to Nagihiko (Kukai asked Nagihiko what it was like in a skirt and angered him). The figurine earlier found belonged to Yugaku, who is not only a strong karate student, but also has a love for anything cute. Easter is studying Ikuto's violin and they want to put X Egg energy into it. Lulu comes by to the Iwagaki dojo and takes advantage of his love for cute things, turning his Heart's Egg to a Mystery Egg. When Amu comes by, Yugaku Character Transforms to Fancy Dream and makes a mess of the dojo. Amu and Rima transform to Amulet Spade and Clown Drop, but after being outnumbered, Su switches in, becoming Amulet Clover. Clearing up misunderstandings, Amu performs Open Heart to purify him.

The Guardian Characters go to Ami's class, the Kindergarten Plum class. Everything appears to be going well for them with all the Guardian Characters playing with the children. Panic comes when Nana spots a frustrated student, Maa. Lulu is told of this and manipulates the child, turning his Heart's Egg to a Mystery Egg. Ami tags along with Amu and the Guardians to go home. Amu and the Guardians notice Maa, and Character Transforms into Amulet Heart. After fighting with clay statues, which keep molding over and over again, Miki switches with Ran. Amu tries to convince Maa to stop, but he ignores her. Finally, Amu says that she will get mad, and Maa hears. She tries to purify him, but after a while, Maa finishes his clay model of Kiseki, and is so happy, that his egg becomes purified, which causes the statue to collapse. Kiseki mourns for the statue after the collapse. The group is glad Maa is okay, and they head home. Maa's mom comes, and Maa insists she buy him origami paper because he is "done with clay". At the end, Ran, Miki, Su, and Amu find out that Ami has gotten a "Guardian Character House!" for Ran, Miki,and Su to make them happy.