On a dark, wet London morning in 1857, Chester Ludlow, an American engineer, arrives on the muddy banks of the Isle of Dogs to witness the launch of the largest steamship ever built, Isambard Kingdom Brunel's The Great Eastern. Ludlow, propelled by fierce ambition, is a key member of a small consortium whose ambition is to lay the first transatlantic telegraph cable. He has abandoned his fragile wife, Franny, on their estate in Maine. The couple are still in deep mourning for their daughter who died in a tragic accident, aged only four. The charismatic Ludlow meets a woman who will exert the most powerful influence on his life and work - the beautiful and enigmatic Katerina Lindt. As both Ludlow and Franny's lives start to unravel, they find themselves caught up in a relentless tide of change crashing across both continents and blurring the boundaries between the physical and the spiritual worlds.