Could you turn flax into gold? Well grettle did. Only it was a misunderstanding. She could turn the word flax into the word gold by changing one letter at a time but not into real gold.

The king on hearing of this amazing feat summons Grettle to the castle where she is placed in a tower with a load of flax to turn into gold or be beheaded. A gnome appears and offers to turn the flax into gold in exchange for her first born child which she eventually agrees to.