72 hours

The Royal Navy's dramatic race to save the crew of a trapped Russian submarine. 5 August 2005. On a secret mission to an underwater military installation 30 miles off the coast of Kamchatka, Russian Navy submersible AS-28 ran into a web of cables and stuck fast.

With 600 feet of freezing water above them, there was no escape for the seven crew.

Trapped in a titanium tomb, all they could do was wait as their air supply slowly dwindled. For more than 24 hours the Russian Navy tried to reach them.

Finally - still haunted by the loss of the nuclear submarine Kursk five years before - they requested international assistance.

On the other side of the world Commander Ian Riches, leader of the Royal Navy's Submarine Rescue Service, got the call: there was a sub down. With the expertise and specialist equipment available to him Riches knew his team had a chance to save the men, but Kamchatka was at the very limit of their range and time was running out.

As the Royal Navy prepared to deploy to Russia's Pacific coast aboard a giant Royal Air Force C-17 airlifter, rescue teams from the United States and Japan also scrambled to reach the area. On board AS-28 the Russian crew shut down all non-essential systems, climbed into thick thermal suits to keep the bone-chilling damp at bay and waited, desperate to eke out the stale, thin air inside the pressure hull of their craft.

But as the first of them began to drift in and out of consciousness, they knew the end was close.

They started writing their farewells. 72 HOURS tells the extraordinary, edge-of-the-seat and real-life story of one of the most dramatic rescue missions of recent years.