Ned cannot interpret his strange dreams of the sea, or understand why his sister, Nell, can hear the ocean’s footsteps.
Then the great spring tide brings three strangers to their home and the terrifying past comes closer…
Ned and Nell learn about a girl called Ultramarine, who is the reason for their grandmother’s hatred, not only of the sea and all its creatures, but also of them.
Only Arion, a man from the sea, can help them. But is Arion real or a ghost? Sometimes he disappears, leaving footprints that never fade… How can he protect them?