Once Upon a Time is put together in a seemingly complicated way. There is a continuous plot that is broken up into chunks and then put back together in a dis-continuous way: you have to put the pieces together in your imagination -- it requires some work.

There are two worlds in this series: the Faerie World and the Real World. The two do indeed intersect at times. And that is one of the things that gives the show its charm.

I hope you learn something from it.