The Héla are a people that lives under the earth. They are made out of ice and have a very strong connection with nature. Earth shows them memories from different times and places and in return for that they give her a bit of their energy, as the planet is weakened by the reckless ways of the humans. 

One of the Hèla, called Sini, tells us that a lot of her people climb to the surface and die there, because the humans break their hearts.

Sini hates the surface, but one day she accidentally steps into the sunlight that shines into the caves and from that day onwards she is addicted to the light. She wants more and more of it until she climbs unto the surface. She remembers her connection to the sea as she is made out of frozen saltwater. She finds a beach and decides to stay there. On her first day there, she meets the human Nathan, who lives in the city close by. Both of them are connected by their longing for freedom, which one can feel in water. Sini despises the humans mostly because they destroy earth, but she befriends Nathan. Despite her not wanting to realise, something more than friendship blooms between them.

But as the two of them start to get closer, dangerous things start to happen and Sini has to fear for her heart.