4 ideas
A sea-king's youngest daughter trades her tongue to a sea witch for human legs; every step feels like walking on knives. She hopes to win the prince's love and, with it, an immortal soul, but he marries a princess he wrongly believes saved him. Given a knife to kill him and return to the sea, she throws it away and dissolves into foam, and her only reprieve is a probationary 300 years as a 'daughter of the air.'
Swindlers sell an emperor cloth they say is invisible to anyone stupid or unfit for office, so every official praises what none of them can see. When a child in the crowd says 'But he hasn't got anything on,' the townspeople repeat it, and the emperor suspects they are right. Yet he reasons that he must go through with the procession, walks on more proudly, and his chamberlains keep carrying a train that does not exist.
Each tale is written in a spoken, childlike voice while carrying a second layer of irony meant for the adult reading aloud. The child receives the plot and the wonder, and the adult receives the satire on vanity, class pretension, and cruelty. The same sentence therefore delivers enchantment to one listener and indictment to the other, so neither listener is spared what the tale implies about them.
In several early tales, success does not go to the virtuous. The soldier in 'The Tinderbox' beheads the witch who helped him and takes her power, and Little Claus tricks his way to wealth and drowns his rival. Andersen tells these outcomes flatly and passes no moral judgment.