This post is totally spoiler. Don't read it unless you have already seen it or read it or don't intend to do either, or don't care if I spoil it. I watched the movie (the one with Sting as Feyd) and read the book (the one with Feyd as Feyd). The idea is that there is this planet, covered with deserts (hence the name Dune) which is the universe's only source of spice. Spice is valuable. The Emperor wants to destroy one of the noble families and does so by pretending to give them the spice planet as a fief only to take it back by force. Things go pretty much to plan except that the son of the destroyed noble family turns out to be a real ersatz hatrack (darn, I wasn't the first to think of that), a kind of messiah. He excapes the slaughter and organizes the indiginous population to not only take control of their own planet, but to destroy the spice crop and replace the planetary ecology that produces it with another. Water will flow and the desert will disappear. There are worms 20 meters in diameter and 400 meters long. I figure the fish on this planet must be something else. I'm not sure how they find nourishment. Packs of them will travel for miles just to eat a single human. I think the expenditure in energy won't be replaced by the meal, not even if they eat me (To give you some idea, I need a running start to get into a compact car). In fact the whole worm, spice thing seems expendible in the story. However, the book is the first in a series of six, so I may find out more as I read on.