John Hopkins

But it won't budge.

Already over his maximum time at this depth, Dave has no choice but to turn and begin his long, treacherous journey back to the surface.

But not before attaching his cave line to the body so that it can be easily found again.

At around 140 meters, he meets his close friend and frequent dive partner, 48-year-old Don Shirley, who has been acting as his support today.

Dave manages to communicate what he has found, and Don gravely acknowledges.

He shakes his friend's hand, then leaves Dave to continue his ascent to the surface.

But they will both be coming back here soon.

Wordlessly, almost telepathically, a decision has already been communicated between them.

What neither man can know is the unimaginable impact this decision will have on so many lives, or the tragically high price which will be paid as a result.

Never wondered what you would do when disaster strikes?

If your life depended on your next decision, could you make the right choice?

Welcome to Real Survival Stories.

These are the astonishing tales of ordinary people thrown into extraordinary situations.

People suddenly forced to fight for their lives.

In this episode, we meet world-renowned diver Don Shirley.

In October 2004, Don and his friend Dave are diving in South Africa's legendary Bushman's Hole, when Dave stumbles on a body in the darkest depths of the flooded cave.

The discovery kickstarts an audacious mission, the deepest body recovery ever attempted.

But in this environment, there is almost no room for error.

Even the slightest mishap can be fatal.

So when, during the dive, the two friends run into multiple unexpected difficulties, a harrowing battle for survival ensues in one of the most hostile and perilous places on Earth.