Dougie Vipond and Duncan McCallum head to the Lowther Hills for the Original Mountain Marathon: a two day test of endurance where contestants have to run two marathons carrying everything they need to survive a night out. It's the oldest endurance challenge in the UK. Also on the show, Lindsay Cannon ventures into Glen Affric to meet some wildlife and we meet a remarkable woman, who is still climbing despite being paralysed from the waist down.