An astonishing debut novel about friendship, trust and survival – with a monstrously big heart.

Two hundred years ago, a series of natural disasters known as the Ruin poisoned the land and caused never-before-seen sea creatures to claim the ocean as their own. For the coastal villages that are all that is left of humanity, they are a constant threat and a frightening story told to keep children out of the shallows. They are precisely what they have been named: monsters.

But when Sunny discovers one of those monsters trapped on the beach, she realises that everything she thought she knew about them is wrong. Mo, as she names him, is an intelligent, gentle creature, far more in tune with nature than humans.

With crops failing on land and hostilities increasing at sea, will Sunny and Mo’s unlikely friendship be enough to save what’s left of their world?