What lies at the bottom of the oceans? This unique documentary follows a group of scientists from Cambridge in the UK and from Russia on a voyage to explore the mysteries of the seabed over 3000 metres beneath the mid Atlantic. Using a state-of-the-art submarine they dive to observe the remarkable hydrothermal vents on the sea floor. These volcanic hot springs known as 'black smokers' may be able to reveal more about the workings of the earth, the chemistry of the oceans and even perhaps the origins of life itself. They are a fantastic new challenge to science emitting matter at several hundred degrees centigrade, giving rise to wholly unexpected forms of marine life that have evolved beyond the reach of light and heat from the Sun. This programme reveals both the challenge of deep sea research and the cultural and scientific exchange between Western and Russian scientists.