26 and in the prime of his life, Paul had the world at his fingertips. That would all change when he suddenly lost vision in his left eye. 24-hours later, Paul would be rushed to the hospital and soon find out he had leukaemia.

From bad to worse, Nathan's trip in Northern America was fraught with danger, violence, deceit but above all understanding. This episode, Clarity, brings you the tale of Nathan and his journey down the Colorado river.

Dreaming of escaping to the wild - albeit within one of America's most popular national parks - I set out to live among nature and make the most of California's pristine backcountry. Hiking shoes: check. Food: check. Ignorance: check.