Hannah is not like the other girls in the turn-of-the-century Boston orphanage where she grew up. Instead of seasickness, Hannah gets land sickness. She leaves a ring of salt in the tub when she bathes and sometimes she sees a faint tracing of scales on her feet.

It's freakish, horrifying ... and deeply thrilling. Hannah feels a change coming. But she is not the only one who senses it. A young painter recognises something in Hannah - a connection with the sea that recalls a secret from his own past. A choice lies ahead and Hannah must discover if she is a creature of the land - or of the sea.