Part 1 left us with a real cliff-hanger on the whole story behind Zuko's mom, so let's all get caught up.
We know Ursa used to be in love with a man named Ikem, who loved her very much. Soon after he proposed to her, she was near forced to wed Firelord Ozai, leaving Ikem sad and miserable.
In the present, however, we know that Zuko and the Gaang are all searching for Zuko's mom, joined by Azula after a discussion with her father while in the mental hospital. Azula had carried a note with her, and Zuko finally read it at the end. Check it out...
Do you think the letter is a fake? Who do you believe is Zuko's father?