When you sleep, your soul briefly returns to the place where it was created/goes to when it dies, and seeks nourishment. Everybody's soul is created with a little link (or you could say a greater entity calls it back) to that place so that it can return easily, but upon death, the soul returns via that and annihilates the link as if returns.
Also, as an added thingy, you could say the entity supplying the link, or residue of the links themselves, (whichever) is the source of all arcane power.
The heroes stop in a small town ready to restock their traveling supplies and feed for their animals. All of the villagers are starving, and there is no food to be had. If the PCs are quick witted, their noble steeds might be slaughtered for food.