Granny Rose travels a long way to visit Mopatop's Shop because she has heard you can get everything you want in the shop. She wants nothing, which is hard to come by. There always seems to be a little bit of something in nothing.
Mopatop and Puppyduck have a hard time finding nothing in the things they thought were empty. In the end, Granny Rose does not leave the shop with nothing. She takes things like the smell of fresh baked bread and a lot of memories with her when she leaves the shop.