A 2.4-mile swim, a 112-mile bike ride and a 26.2-mile run makes the Ironman triathlon one of the hardest one-day endurance challenges on the planet.
Now take those events and transfer them to a volcanic rock with cruel winds, searing sun, rough seas and nosebleed-inducing hills, and you have Ironman Lanzarote.
Why, then, would Andy Holgate - who admittedly has never swum in the sea, who can't cope with the wind, sun or even stairs - take on such an extreme challenge?
Simple: Because he can. Can't Sleep, Can't Train, Can't Stop! continues Andy's inspirational journey from where Can't Swim, Can't Ride, Can't Run left off, chronicling his attempt to complete two Ironman triathlons six weeks apart.
Already in his fortieth year, would Andy make it to his forty-first?
Would Lanzarote prove one triathlon too far - or will Andy succeed against the odds and live to swim, ride and run another day?