Chris Lemons is professional diver from Scotland. His job : maintenance of underwater gas and oil pipelines and platforms. A hazardous occupation, what with the dangers of decompression and the risks of drowning. In 2012, Chris is with his team in a hyperbaric chamber that would be their home for the next few weeks on board a huge ship : four teams of three divers will take turns on this mission, and Chris is delighted to be reunited with colleagues who have an excellent reputation...