Barents Sea, August 12th, 2000. During a Russian naval exercise, and after suffering a serious accident, the K-141 Kursk submarine sinks with 118 crew members on board. While the few sailors who are still alive barely manage to survive, their families push for accurate information and a British officer struggles to obtain from the Russian government a permit to attempt a rescue before it is late. But general incompetence are against all their efforts.

Dr. Robert Ballard of Woods Hole Oceanographic Institute and his research team become the first undersea explorers to locate, photograph, and explore the wreckage of the ill-fated HMS Titanic, which sank on its maiden voyage 2 1/2 mile deep in the icy waters of the Atlantic in 1912, taking 1500 passengers and crew with it to a watery grave. Utilizing dazzling state-of-the art equipment and cutting edge expertise they record the decaying remains of the ocean liner once thought "unsinkable."

An expedition looks into whether Titanic's hull had a construction design flaw that caused her to break apart. Featuring advanced CGI technology, archive documents and photographs, as well as footage from the modern-day History(R) expeditions, "Titanic's Achilles Heel" is a remarkable journey into the ongoing legacy of a ship that continues to capture the world's attention.