In February 2022, Charlie Walker flew to Russia to travel 600 miles alone across Arctic Siberia. Five days later, Russia invaded Ukraine. He had a narrow window to get out - and chose to stay and finish the trip, becoming very possibly the last Western tourist in Russia.

Walker set off on foot from the coldest inhabited place on earth, hiking frozen rivers and ice roads in temperatures down to minus 50. The expedition itself mostly went to plan. The problem was everything around it. With independent media silenced and a new law threatening 15 years in prison for "fake news" about the war, his presence was logged village by village and reported. By the time he reached the coast, he was expected. What followed was an interrogation, a fabricated case, and four weeks in a Russian prison - with the real risk of becoming a bargaining chip - befor ...