Following the events of Body of Water, disgraced Army Medic Shaun returns to London where his life dramatically spins out of control.Drinking heavily, he eventually decides to end his life. Planning to drown himself in the River Thames, he discovers the body of his old flame Leven.Shaun sees this as a sign and takes Leven back to his flat to nurse him back to health, trying to retrieve what he once discarded. Thankfully for Shaun, Leven remembers nothing and Shaun uses this to his full advantage, constructing a history between the men that never happened.But when Leven starts to exhibit power over water, and Shaun is attacked by strange creatures, both men realise that their mutual deaths might have been preferable to the suffering their future holds.