Put the Heart of the Song on Wings!
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 of a store, when a girl walks out. The girl's cell phone rings, and 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 walking out of the building. The two talk, but Miki senses the presence of a ? Egg. They head off to see Hitomi hypnotized, singing and putting everybody in a trance. After Utau criticizes her, Hitomi Character Transforms to Singer 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 ? 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; it was stolen by Easter.
Aired 25/10/2008EP 4 - Put the Heart of the Song on Wings!

Shugo Chara!! Doki
With things having quieted down a bit for the Guardians, they can now focus on things besides fending off the peril of the evil Easter Corporation. Amu is having some troubles deciding which guy she likes the most, and hiding Ikuto in her room. Not only does the Embryo still elude the Guardians, and worries of Easter being suspiciously inactive, the threat of a new X Egg appears...