When the Titanic sank, it took a secret with it . . . In the vast expanse of the Atlantic, 375 miles off the coast of Newfoundland, a ship's crew film an extraordinary event: the ocean, covered with millions of floating fish, bubbles as though boiling. Then an enormous whale roars through the water and crashes down, dead, onto the surface. Some 13,000ft beneath - at these precise coordinates - lies the wreck of the Titanic. Within twenty-four hours, the video has become a global phenomenon. Commander Jerry Derham, charged with investigating the incident, rushes to see marine archaeologists Kate Wetherall and Lou Bates. The one-time couple specialize in deep-sea-diving and the scientific study of shipwrecks. Jerry needs to get the pair down to the ocean floor - fast. None of them are prepared for what they find there. Someone on the Titanic had been keeping a secret: one that cost lives. A secret that has remained trapped beneath the ocean for a hundred years. And now there are those who would kill again to get hold of what one man died for in 1912 . . .