Well. Yes, Po has a family and had nightmares while growing up, which he realises when he faces the Peacock fighter. This movie has all the traditional masala (spicy!) . He realises soon that the father he believed as his, was just a guardian. The Peacock fighter dreams of conquering the country and leaving no Kung Fu fighter coming in his way.
Just Po stands in between him and his throne.
Inner peace is the sought out word in this part, like in earlier was the confidence Po lacks for Kung fu fighting.
This series has some comic feel to it, but develops seriousness in between light moments.
The Panda family comes into picture at the credits, making a way for the third part, or the second sequel.
Poster from Wikipedia.