Anthony Fennell, an Irish journalist and playwright, is assigned to cover the underwater cables that carry the world’s information. The sum of human existence --- words, images, transactions, memes, voices, viruses --- travels through the tiny fiber-optic tubes. But sometimes the tubes break, at an unfathomable depth. Fennell’s journey brings him to the west coast of Africa, where he uncovers a story about the raw human labor behind the dazzling veneer of the technological world. He meets a fellow Irishman, the mysterious John Conway, who is a skilled engineer and a freediver capable of reaching extraordinary depths. When the ship is sent up the coast to repair a series of major underwater breaks, both men learn that the very cables they seek to fix carry the news that may cause their lives to unravel.