In our World, we like to think of ourselves, as top of the food chain. This movie reminds us, that we aren't as safe, as we might think.  There are Worlds and Worlds, beyond our own, and to them we are but resource to feed their unseen god.

 

Two are sent with the responsibility to return many.  It is hard living amongst a food source so attractive, yet venerable to a kind smile, or zap from unsuspected powers.  They only have to not do the forbidden, or that which is Taboo.  To break Taboo, will make you into that, which you seek.