Helen Dunmore 
Stormswept 

An atmospheric and beautifully written adventure, from the award-winning author of the Ingo series.Morveren lives with her parents and twin sister Jenna on an island off the coast of Cornwall.As Morveren and Jenna’s relationship shifts and changes, like driftwood on the tide, Morveren finds a beautiful teenage boy in a rock pool after a storm. Going to his rescue, she is shocked to see that he is not human but a Mer boy.With Jenna refusing to face the truth, Morveren finds herself alone at the worst possible time. Because when the worlds of Air and Mer meet, the consequences can be terrible…