Animation where boy has to find imprisoned mother who is turned into a mythical creature

Movie begins with boy and his mother in a temple or palace of some sort arguimg with mother’s brother or father who is powerful. I think a God or priest but I’m sure has magic. He imprisons the mother or turns her into a mythical creature and seperates her from her son. The son now being alone in the world has to find his way back to his mother. I think also he might have a lamp or some sort of object. I watched this as a child and this is all I remember. Any help with the title will be very much appreciated

Kubo and the Two Strings