Birth! Double Character Transformation!
In the middle of the heated battle between Ikuto and Tadase, the Humpty Lock and Dumpty Key come up. Amu and her friends were wrapped in an overwhelming amount of light when a memory of Ikuto appeared. Based on one conclusion; the secret of the violin, the birth of Yoru - the past of Ikuto becomes clear. Amu realizes that the power of her two guys differ. Source: crunchyroll
Aired 12/09/2009EP 49 - Birth! Double Character Transformation!

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...