Anthony Fennell, a journalist, is in pursuit of a story buried at the bottom of the sea: the network of tiny fibre-optic tubes that carry the world's information across the ocean floor - and what happens when they break.

So he has travelled to Cape Town to board the George Lecointe, a cable repair vessel captained by Chief of Mission John Conway.

Conway is a talented engineer and fearless freediver - and Fennell is quickly captivated by this mysterious, unnerving man and his beautiful partner, Zanele.

As the boat embarks along the west coast of Africa, Fennell learns the rhythms of life at sea, and finds his place among the band of drifters who make up the crew. But as the mission falters, tensions simmer - and Conway is thrown into crisis. A terrible, violent tragedy is unfolding in the life he has left behind on land; and, trapped out at sea, it seems as if the vast expanse of the ocean is closing in.

Then Conway disappears; and Fennell must set out to find him.