* Sea-dwelling merfolk: The most significant difference is the existence of merfolk, who live in the oceans and have a society and culture of their own. They are able to breathe underwater, and have tails instead of legs.
* Magic: The merfolk possess a form of magic, which they use for various purposes, such as healing, communication, and controlling the tides.
* Hidden world: The merfolk are generally hidden from the human world, though some, like Emily's family, live secretly amongst humans.
While the exact location of the story is never explicitly stated, it is likely set in England, as the book mentions references to places and events that are familiar to the UK.
Here's a breakdown of the key settings in the book:
* The Windsnap family's home: This is a house in a coastal town, likely somewhere in England. It is where Emily lives with her human mother and merfolk father.
* The Sea: The underwater world is a major setting in the story. The merfolk live in a complex society with its own rules and traditions.
* The Ocean Academy: This is a school for young merfolk, where they learn about their culture, history, and magic.
* The Isle of the Mer: This is a mystical island that is home to the merfolk elders and their most sacred shrine.
The setting is key to the story, creating a world where both human and magical elements coexist, and where Emily must navigate the complexities of both.